How to clear cloudy aquarium water

Lion fish in blue aquarium water

What is cloudy water?

In short, it’s a bacterial bloom. However it is not the beneficial bacteria normally referred to as nitrifying bacteria. Before those get to work, another set of bacteria is needed. These “scavengers” are heterotrophic bacteria, which feed off organic waste in the fish tank.

This feeding process represents the first stage of the aquarium’s natural nitrogen cycle, at which organic waste is converted into ammonia. The nitrifying bacteria on the other hand continue the process by breaking down ammonia into nitrites, and nitrites into nitrates, completing the nitrogen cycle. Heterotrophic bacteria can double in population every 20 minutes. Its growth depends on available organic waste in the aquarium. In other words, everything that decays in the fish tanks represents a food source for these scavengers. This excessive growth turns the aquarium water cloudy.

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How do I clear cloudy aquarium water?

As a first course of action the gravel should be vacuumed using an aquarium siphon. This is where most organic waste accumulates and also where the scavenger bacteria initially grow. If large decorative ornaments are in the fish tank it’s a good idea to move these from time to time in order to vacuum the gravel underneath. The goal is to remove as much accumulated waste from the gravel as possible.

Some other things that will help

  1. Reduce feeding. Most organic waste introduced into the fish tank is from fish food. Overfeeding is common and probably the main cause for cloudy water problems.
  2. Do not perform large water changes. While the intentions may be good, large water changes can severely affect the balance of the aquarium leading to a further deterioration of the water quality.
  3. Consider your fish population. A severely overstocked aquarium will result in excess waste. The general rule of thumb is not to exceed 1 inch of fish per 2 gallons of aquarium water.
  4. Be patient. Taking any or all of the above actions is a step in the right direction. However, the fish tank will need time to balance and recover once favorable conditions are created.

Also see our ‘Aquarium Maintenance and Fish Care Tips‘.

And make sure you check out Algone for clearing cloudy water and removing nitrates and impurities from the aquarium.

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95 thoughts on “How to clear cloudy aquarium water

  1. Jackie Ritchie says:

    Hi there I have a 22 litres and 6 neon tetras and 6 Elden guppies, I have had tank for about two weeks and tank was clear and Fish were thriving then the boy in pets at home told me to take 25% water out yesterday which I done and everything was ok and I changed took two artificial plants out and put in a bridge , then by mistake I put a block of blood worms in which was wrong as my neons were getting fatter so I tried to get some out , then I was worried about fish but they were ok today , so tonight I took most of blood worms out and added a solution called clear , but it is now cloudy and my neons are fading colour, what should I do ? As it was all ok before I changed water

    • Thilo
      Thilo says:

      The aquarium needs to cycle first. This involves bacteria to colonize. Their main function is to keep the environment safe for the fish by converting ammonia to nitrite and nitrite to the less harmful nitrate. Ammonia is created by the fish, but you also helped with the worms. This is a natural process and quite essential for the health of the fish. The cloudiness is the first bacteria to settle, they grow at rates that turn the water cloudy. These bacteria create the ammonia. You likely have ammonia readings, this also stresses the fish and can be the reason why they loose some color.
      Please read more on the cycle here: https://www.algone.com/the-aquarium-nitrogen-cycle

  2. daisy says:

    I got my fish tank about 3-4 days ago and left the filter on like instructed. The water was crystal clear and I was proud of my new purchase. I woke this morning to see a white cloudy, murky kind of water. I did dechlorinate it as well PLEASE HELP!!!

    • Scott @ Algone
      Scott @ Algone says:

      No need to panic. The white cloudiness is likely a bacterial bloom. Nitrifying bacteria need to establish in a new aquarium and the water my become a cloudy white in the initial stages. This should clear up on its own. Avoid aggressively large and frequent water changes believing you are solving the problem. This will only lead to a prolonged period of biological imbalance. Slow, incremental changes are key to aquarium success. Feed only once daily, sparingly and don’t overcrowd the aquarium with fish, and things should clear up on its own.

  3. Nicole says:

    Over tried everything vacuum changing 25 percent of water it a 20 gallon tank I only have 4 fish it been cloudy for 2 weeks now the levels are good I had them checked I’ve changed filter put clear drop water conditioner I’m at a loss help 1st it was an light orange brown color now it’s gray HELP

    • Scott @ Algone
      Scott @ Algone says:

      This sounds like it may be a bacterial bloom since it’s a gray cloudiness. Read more about bacterial blooms in aquariums here.

      Also be sure not to overfeed. We recommend feeding your fish no more then once a day, sparingly at that. Most all aquarium problems stem from accumulating organic waste, which comes almost exclusively from fish food.

      • anthony says:

        Hi ,in regards,feeding once a day,,including fry,,living in the same tank,,just once a day?,,,,I have also heard leaving light on too much can make water cloudy,,,true or false?,,,,Thank you.

        • Scott @ Algone
          Scott @ Algone says:

          You can feed fry 2 – 3 times a day. Just make sure you cut down on food per feeding. You shouldn’t need to do this for more then about a week. Also, don’t spot feed. The idea of feeding more frequently is to give fry the opportunity to compete for food, so a little pinch of food in a few different areas of the tank, per feeding, will help distribute the food better and give the fry a better chance to get what they need.

          Yes, leaving the light on too long can make the aquarium water cloudy. Cloudiness caused by excessive light is an algae bloom and will be green. Algae require light, nitrate, and water to grow. We recommend lighting during times you are around the aquarium only. Try to limit total lighting time to about 5 hours per day, from 4pm – 9pm for example.

  4. Isabella Winter says:

    Hi, I have had my betta fish for about a month now and his tank has gotten very very foggy. I need help! My bowl is about a 2.5 gallon. I think I might have been over feeding him a little but now I have stopped over feeding him so Idk what to do!

    • Scott @ Algone
      Scott @ Algone says:

      You can change about 15 – 20 percent of water, while siphoning waste from the substrate, every few days to help clear the water. You said you cut back feeding, you might want to consider feeding sparingly only once every other day. A 2.5 gallon aquarium of water will quickly pollute and turn cloudy or experience green water / algae outbreak, compared to a larger tank. Read more about the challenges of small aquariums here.

    • Daniel says:

      If your are over feeding him you should add some ghost shrimps. The will eat some of the waste of the fish and the leftovers.😀😀😀

  5. Marianne says:

    I have been battling cloudy water in the fish tank. It is a 36 gal bow front & was brand new when I got the set up for Christmas. I had been over feeding the fish. About 4 weeks ago I did a 75% water change & changed the filter cartridge & bio media. The water looked great and all levels normal. After a week or so the water started to cloud again so I added water clarifier and it cleared for a few days. Today I did a 30% water change also vacuumed the gravel and the water is still cloudy. All levels are normal however Ph is a tad low at 6.0.
    What can I do to keep from having cloudy water? Any advice would be greatly appreciated!

    • Scott @ Algone
      Scott @ Algone says:

      Hi Marianne, our general rule of thumb for aquarium maintenance is ‘less is more’. You correctly identified that you were overfeeding, so correcting that was a great first step.

      I suspect when you changed 75% of the water and also changed the the filter cartridge and bio media, you essentially threw the tank out of balance. This is where less is more. A big change, like you described, will interfere with healthy bacteria growth within the tank. Nitrifying bacteria are needed for a healthy aquarium environment. With your changes, your aquarium likely needed to “cycle” again.

      In case you’re not familiar with the nitrogen cycle, the phrase ‘cycling’ refers to the first 4 – 6 weeks of a new aquarium, at which time nitrifying bacteria are established, making the fish tank habitable for fish long term.

      Check out these articles for more information:

      Nitrogen Cycle
      Nitrifying Bacteria
      Biological Filteration

    • Christine says:

      I would suggest feeding tiny amount day and night.I have Angels who have paired of now and layed eggs so about 2 years now I’ve had them when I get carried away and fed to much my water always clouds I use 1 and only 1 thing in my tank it’s called Prime everyone who I know that uses it uses it alone with nothing else since I
      Began using it I haven’t lost a fish.But if I over feed it does cloud my water when it happeneds it always clears up again save your money nothing will clear it but time it will clear.

  6. lorraine Avallone says:

    Have. 3 Tanks .But Having Cloudy problems with My 70 Gallon . Tried Acurel and still problem still Excisting Please Help.Dont want My Fish to Die

  7. Gretel Gonzalez says:

    Hi I forgot to ask I have aquasafe that makes tap water safe for fish it does it have an expiration date but it does have a fishy smell I don’t know if that is normal it’s been awhile, my daughter bys Water Conditioner by Top Fin and we ran out and unfortunately she had a baby and he was a preemie and she is at the hospital with him which is 40 minutes away from here and I had no idea that she ran out of this stuff so I went ahead and ordered from chewy.com and it will be here tomorrow but I really really need to clean this fish tank because I don’t think the fish could even see and I’m afraid that they might die. so like I asked in my other question is home remedy that I can use or can I use this aquasafe that makes tap water safe for fish that smells kind of fishy that like I said I don’t know if that’s the way it’s supposed to smell? I would appreciate an answer as soon as possible thank you very much.

    • Thilo
      Thilo says:

      Yes it does have an expiration date, but it is not uncommon for some conditioners to smell. Generally fine to use within 3-5 years. Refer to the manufacturer for details.

  8. Gretel Gonzalez says:

    my fish tank is extremely cloudy In you cannot see through it I just ordered to chewy.com everything I need to clean it I also ordered a new filter with filters but it will not arrive here till tomorrow and I really need to clean this fish tank I need to know how to do it yourself idea on how I can do it myself or what I can put in there? I would greatly appreciate it I don’t want my fish to die I have one picasimus he is about 5 inches long and I have 2 giant goldfish I am not sure the real name but they are one is about 4 in Long and the other is about 6 inches long, they are just beautiful and I do not want to lose them.

    • Thilo
      Thilo says:

      No matter if you have white or green cloudy water, the reason is always a high nutrient level in the aquarium. There are three main causes for high nutrients levels, tank size in relation to the fish being kept. overfeeding, or limited maintenance.
      Cloudiness can occur during the initial start up phase (cycle) because excess waste is not processed as efficiently compared to an established tank. It can also occur once the fish matured, and or if aquarium maintenance needs improvement.
      The best solution is always to correct the problem, without it, cleaning will be temporary and the cloudiness is bound to return.
      Here are two links with specifics:
      https://www.algone.com/what-causes-milky-white-cloudy-aquarium-water#comment-451347
      https://www.algone.com/how-to-control-aquarium-algae

  9. Tamarra says:

    I have a 10 gallon tank with 8 Molly fish . Everything was going good but recently the water keeps getting cloudy , I have changed filters, water, rocks and added water conditioner as well as clear water . Someone please help me

    • Scott @ Algone
      Scott @ Algone says:

      You should checkout this article about ‘New Tank Syndrome‘. Changing the filters and water, usually has the opposite of the desired effect. Nitrifying bacteria establish in the first weeks of a new aquarium. This bacteria is needed for a healthy tank, because it breaks down organic waste.

      The waste is almost exclusively from fish food, therefore you must feed responsibly. Our general recommendation is to feed only once daily, sparingly at that. If you are experiencing cloudy water or algae growth, cut feeding to once every-other-day. Fish have a slow metabolism and do not require anywhere near as much food as most food manufacturers recommend.

      Water changes generally should not exceed 20%, and should not be performed more frequently then 5 – 7 days.

    • Scott @ Algone
      Scott @ Algone says:

      Technically speaking, yes. If it works out in practical terms however is questionable. The introduction of good bacteria into the aquarium should help reduce nutrients such as nitrate, which are a food source for algae growth. However, once the bacteria has been added to the water, the aquarium will re-balance and quickly return to the state in which it is now. So results will be temporary at best.

      For a more sustained effort eliminating aquarium algae, reduce the amount of waste entering the tank by cutting feeding to once a day (sparingly) and avoid overstocking the tank. Also consider Algone, our natural nitrate remover and water clarifier, to help keep nutrients low.

  10. Betty Cundiff says:

    We remived the fish, from iur 160 gal. Tank for complete cleaning.Took out everything, washed and cleaned entire tank inside and out. Refilled the take and added the Declor and AquaSafe let the water warm to between 75 & 80 degrees at which time we floated the fish for aprox. 30 minutes. Then introdused the fish to the the clean tank. However the water started turning cloudy within a ciuple hours and is still cloudy today ( whats up ?)

    • Thilo
      Thilo says:

      You cleaned away the bacteria that make the water safe for the fish. There are several species of bacteria, heterotrophic bacteria break down organic waste, and the beneficial bacteria oxydize waste into ammonia/ nitrite/ nitrate. The bacteria settle anywhere in the aquarium. Cleaning too thoroughly literally wipes them out. Especially the heterothrophic bacteria. These then re-populate the aquarium and that is what turns your water cloudy. You might have enough survivors on the beneficial bacteria, but watch for ammonia.

      Here are general tips for maintenance: https://www.algone.com/aquarium-maintenance-tips-and-fish-care-guidelines

  11. Rhonda burbridge says:

    I have 2 Oscars that are about 3 yrs old…one black and one goldfish orange..I have them in a 65 gallon tank.is this the right size of tank for their growth?

    • Thilo
      Thilo says:

      65 Gallons would be on the very low end having two Oscars. These are big fish and need some room to swim around freely without bumping into walls or tank mates.

  12. Raj says:

    hi
    I have an aquarium size of 36×18×24 (l×b×h). I have got oscars and 4 tinfoil. These are not so big. The water is cloudy. How do I keep it clear? And I use the food tidbits.
    help

    • Thilo
      Thilo says:

      That would be about 65 Gallons … your aquarium is too small for the fish you are keeping. Oscars and tinfoil barbs easily grow to 12-15 inches. Your aquarium will not be able to sustain these fish and more problems are likely to ensue. The best advice is to get a larger aquarium, or more suitable fish for your aquarium.

  13. Susan Groundwater says:

    My water is extremely white and gree cloudy.I have multiple fish and variety. Some are dying. I’ve tried water changes clarifyers nitrate and nitrite mediums but the water has a greenish tint to it now. What can I do to clean the water? I started with well softened water but have used bottled water for changes. At least 20 gallons in a 20 gallon tank. It just gets worse.

    • Thilo
      Thilo says:

      Green water is caused by excess waste and influenced by many factors. So is the white discoloration. Overstocking, overfeeding, wrong environment, plants not doing well, substrate, filtration, light, there is an endless list of possibilities. Please contact customer service with more details on your situation.

  14. Irehm says:

    Hi! I’ve learn so much from the A/Q, thanks! I just set up a 25 gallon planted fresh water tank. Water pH was 8.2 so I used neutral buffer and it become super cloudy. My filter is whisper 30i it has been 2 days and no changes in the water color. What should I do?

    • Thilo
      Thilo says:

      PH reducing additives can cloud the water, but the cloudiness will eventually resolve itself. Technically, most plants and fish will adapt to higher pH levels, but it depends on the fish and plants you are keeping. Make sure to test the water you use for water changes to determine the pH of the incoming water. If plants and fish tolerate higher pH, do not fool around with it. If you need to lower the pH, consider and alternate water source, or use peat moss, or driftwood to lower the pH. If the aquarium is new and has not, or is cycling, wait a few weeks to see where the pH ends up to be once the cycle is complete before taking any action.

    • Scott @ Algone
      Scott @ Algone says:

      Yes, run the filter. It’s quite normal for the tank to initially be cloudy due to free floating particles from the gravel.

      • Stevens Tim says:

        How long til it clears I did the same think .I washed the rock first ,filled up the 29 gallon, very cloudy .I syphoned about 40%water n rock then added new water .Should it be clear in a few days ?

        • Scott @ Algone
          Scott @ Algone says:

          The aquarium should clear in only a day or two with the filter running. If it doesn’t, the cloudy water is likely not just particles from the substrate.

  15. Lou Howard says:

    I have a well established 36 gal, fresh water tank with 6 small fish in it. The water in the tank has been cloudy for about a month now and does not seem to get clear noi matter what I do. I change some water on a good schedule and do not overfeed. What is the problem?

    • Thilo
      Thilo says:

      After making sure that the water parameters are within tolerances check on your conditioner. The conditioner should not contain bacteria, if it claims to, replace the conditioner with a very basic version without bacteria or bacteria additives. Additives that influence pH can cause a cloudiness. Additives containing calcium can cause cloudy water as well as some phosphate removers.

  16. Stephanie says:

    I have brought a fish home feom where i work i bought a used 15 gallon tank and set it up had to add the gravel and water dechlorinator when i brought him home however this fish was in a big tank at work like a 200-300 gallon maybe the water has clouded up i might have over fed him cause he is used to 2 times a day however he has white strips across his eyes with a white ball in the middle of the stripe what can i do to help him and the water

    • Scott @ Algone
      Scott @ Algone says:

      Please see our summary of common fish diseases. We recommend asking your local fish store for possible treatment options. They should be able to help you identify any disease and choose the appropriate treatment.

      As far as your cloudy aquarium water is concerned, please review the following articles for additional information about the causes and possible fixes:

      White Cloudy Aquarium Water
      Green Aquarium Water
      Cloudy Water and Algone

      I would definitely recommend cutting back on feeding. You can feed as little as once every other day. Fish have a very slow metabolism and don’t require multiple daily feedings. If the cloudy water is caused from overfeeding, cutting feeding to once every other day should help clear it up again. Also consider using Algone, which is an excellent aquarium water clarifier and also reduces harmful nutrients in the fish tank.

  17. Carl says:

    Hi I have had a cloudy water issue in my aquarium now for about two weeks now I have tried fluval quick clear but it hasn’t worked.i do regular water changes but nothing,it’s not bacterial bloom

    • Thilo
      Thilo says:

      If it is not a bacteria bloom, then is is an algae bloom? You can search our site for relevant articles that will provide more detailed info. In a nutshell, algae need nutrients, water, and light. If all is available in excess, an algae bloom can occur. The best way to resolve the issue is to remove the excess nutrients (nitrates/ dissolved organics) It will take some time and you should refrain from the temptation for large water changes or any other dramatic change. It will just cause other issues, but the problem will remain.

  18. Ailene says:

    Hi, i just got a fish tank for the first time ever. I just start it 2 days ago with the filter but just yesterday i put the thermometer, light, oxygen, Conditioner and some decorations. This morning the water looks really dirty or cloudy how some people call it. What should i do? Change the water? Leave it? When can i pit fish in there? Thank you for your help!

    • Scott @ Algone
      Scott @ Algone says:

      Just let it settle for a few days and it should clear up. If you also experience a white cloudiness, that is usually a bacterial bloom and should clear up on its own as well.

  19. nydia says:

    Hi, I have a new aquarium I think is 15 to 20g, I prepared it and put some decor and filter 4 days before adding fish, I put 7 fish, the 2nd day it got cloudy, after reading here I realized this is normal. Is now clearing up, my question is about oxigen, I keep reading about oxigen levels, how can I know my fish oxygen levels are good? Oh and how often do I wash the tank? Do I remove the fish and change water? Sorry this is new to me

    • Thilo
      Thilo says:

      For as long as your filter outlet provides a disturbance at the water surface, you will be fine on oxygen. You never wash the tank, ever. Use a siphon and take 10-15% of the water out of the aquarium gently grazing the substrate. Refill the aquarium with water (use a conditioner prior to adding the water). Go this every other week. Once a month, rinse out the filter, never scrub, just rinse. We have a maintenance schedule online https://www.algone.com/aquarium-maintenance-tips-and-fish-care-guidelines

  20. Steve N says:

    I have a 20 gallon aquarium, it has been home to guppies for 10 years. We got an green algae bloom that obviously, got some attention, it was right as I got the bloom under control the filter failed beyond repair, 12 hours until I could get the new Marineland filter and installed. Five hours later we lost power for 16 hours. That was five days ago. After the filter ran for 24 hours I swapped, a bit more than a third of, the water, and changed the filter packs. I still have a cloudy, milky white not green at all, water condition. The lights have been off for 36 hours. I am only seeing a 5% improvement at best. I have not experienced anything like this before, any thoughts?

    • Steve N says:

      I forgot to add, I put an extra air stone in, in case it is a bacteria bloom from the new filter getting it’s levels up. The water change I did included vacuuming the substrate. Thanks again for any thoughts you may have…

    • Scott @ Algone
      Scott @ Algone says:

      It’s probably best to just stick to 15 – 20% water changes. It sounds like your biological filtration is out of whack after all that and needs time to recover. For nitrifying bacteria to come back into a healthy balance, consistent tank conditions are required. The treatment of the algae bloom, the failed filter, as well as the complete replacement of the filter along with a 33% plus water change have likely thrown the tank out of balance. Now that everything is up and running again and no major changes are being made, time should clear up the white cloudiness. You may also wish to cut feeding to once every other day while the tank is cloudy. This will help cut down organic waste entering the tank and should hasten the process of balancing. Your fish will do just fine on that amount of food as they have a very slow digestive metabolism and really don’t require all that much food. Overfeeding is generally the number one reason for algae outbreaks and other problems related to poor water conditions.

      • Steve N says:

        That was my working assumption as well. Like a perfect storm, the aquarium balance was hit from every side at once. The water change was only to clean the substrate, after the algae bloom and crashed filter, the substrate was not pretty, haha. I think the original algae bloom was caused by a broken window treatment at the right time of the year, for there to be an exposure of direct sunlight, in the morning hours, working graves, I tend not to see early morning events, haha. For now, we wait…

  21. jennifer buchanan says:

    I have had a tank running for over a month i added my fish as i have had consistent levels. But now my water is constantly cloudy. I am fairly new to fish and got alot of info from the store i have a 15g tank i have 3 rainbow fish and 6 dwraf sharks and 3 apple snails…..could the snails be the problem??? I have plants in there as well but the snails are eating them at night.

    • Thilo
      Thilo says:

      As things get crowded, and you are pushing the limits of your tank, the environment deteriorates, especially if you have a maintenance schedule that needs improvement. Plants that are not thriving will also contribute to the issues. I take from your first sentence that you just added fish? In this case the tank needs to re-adjust to the new bioload. That often triggers a whitish discoloration sometimes followed by a greenish tint. The whitish discoloration is a bacteria bloom, the consequence of the aquarium adjusting. With all the new waste to be processed, waste accumulates until there is a sufficient amount of bacteria present. Make sure the water is well oxygenated as bacteria use up good amounts of oxygen.

  22. Jody says:

    I have a 30 gallon tank, the water is so cloudy and a touch of greenish color, I’ve added chemicals and changed half of the water. But no matter what I do it still gets cloudy, I’m wondering, could it be the well water? I hate to spend money to purchase 30 gallon of water and to have the same problem.

    • Thilo
      Thilo says:

      Yes, it could be the well water. This water source can contain contaminates that fuel algae growth, iron, copper, phosphates, just to name a few. You can have your well water tested to make sure. The beneficial aquarium bacteria, fish, plants etc have a much lower tolerance of what we would consider harmless for human consumption. You can look into a water purifying system or an R/O unit.

  23. T Anderson says:

    I have a 40 gallon breeder tank and my water is cloudy. I have no fish in the tank, I do have decorations, and substrate. I did thoroughly clean the substrate for about 20 minutes per bag. I have the Quietflow 50 filter and Aqueon 100watt heater. My ammonia levels are at a constant 0 also my nitrite and nitrate levels are 0. Am I doing sonething wrong with my tank to cause the cloudiness.

  24. mike chocha says:

    Hello i used to have like 5 or 6 tanks all over that house when that kids were in they tens that was like ten years ago, a week ago my grand daughter which she is a year and half went to the hospital she had a high fever but thank god it was just a cold any how when i arrive at the Hospital she was really upset so i took her to the lobby and we found a beautiful fish tank in a corner she initially didn’t like it until i stared to show her that fish and she calm down and ot was like she wasn’t sick at all, anyhow two later a older client of mine ask me to clean out he’s back garage it took me three hole days any how there was 75 gallon fish tank full with drifwood and i took it home wash it with a clean rag and white vinegar and then rinse with a lot of water and the driftwood i clean with a brush and lots of water anyway bought a filter for 75 gl and a light fixture for the hood in home depot set everything up and i fill the tank with water to say the least my grand daughter loves it well at least the first two days today my daughter came in and say moso soup, this thing is almost black water forget the tea or whatever also they call it , i took out all that driftwood we can only see what was in front of glass , im really disappoint it specially for my grand daughter.. I guess my question is what can i do. Ps sorry for that long as letter thank

    • Scott @ Algone
      Scott @ Algone says:

      Sounds like the driftwood leached into the water. Removing it was a good first step. Try using activated carbon in your filter, replacing it every few days until the tank has cleared up. Also consider doing a 15 – 20% water changes every 3 to 5 days as this will help clear up the aquarium as well.

  25. DJ says:

    I just set up my 50gal tank it’s been running for about two days I haven’t added fish yet because my water got milky cloudy why is this and how do I fix this

  26. Dana Hall says:

    I have a small 3.5 gallon fish tank with a small filtration system in my classroom with one goldfish in it. There are small rocks at the bottom of the aquarium. I have noticed that over the last couple of weeks (we have had the fish for almost a month now) the water has turned cloudy. I need to know what we can do to make the water sparkling again and to make sure “Fred” is well taken care of. Please advise on what I need to do to make the aquarium shine again and how do I go about cleaning the aquarium. Do I remove the fish from the tank and wash out with distilled water? I need advice. The last thing I want is to come in and have to tell my kids that Fred is dead!

    • Thilo
      Thilo says:

      An initial cloudiness (whitish) can be expected with a new setup. Bacteria settle to make the water safe for the fish. In cases, the bacteria colonies grow at speeds that turn the water withish. You can use Algone to speed up the process for the water to clear. From there, and in general, the most important factor is not to overfeed the fish. Just a small pinch per day will do. This together with weekly 10-20% water changes using a siphon to vacuum the gravel. A small aquarium is more affected by changes than a large aquarium. Temperature for one, but also chemical/ biological factors are more easily influenced due to the smaller water body. Following a strict maintenance routine is therefore of the essence to keep the water clear and the fish healthy. Please do not remove the fish from the aquarium. The fish has a protective slime coat and frequent removal might damage the protective coat.

  27. Jesus says:

    Hi i have been a fishkeeper for a while with a prtty standard 55 gallon with crystal clear water, my brother just recently got a starter kit with the ten gallon and all that, he asked me to do the set up so I cycled it washed the decorations toroughly i used water de chloeinerez and i acmimated the fish it was all good the first day but over night it got all milky and cloudy, i have never seen this in my fifty fice, what do i do?

    • Scott @ Algone
      Scott @ Algone says:

      White cloudiness is caused by a bacterial bloom. In short, the tank has to come into balance. With a new tank this usually clears up on its own fairly quick. I would recommend avoiding large water changes or any other big changes while the tank is cycling. During the break-in period, the aquarium will eventually balance as long as it is given adequate time and also conditions are consistent. Obviously your brother should avoid overfeeding and overstocking the tank as well. A ten gallon tank is more difficult to keep then your 55 gallon. The small tank volume will require more diligence because waste will have a greater impact. So again, I can’t stress enough to make small incremental changes only. Cloudy water often prompts newcomers to do large water changes with good intentions. What really happens however is that balancing the aquarium is delayed because of it.

  28. robert says:

    i have a small fish tank with 5 shubukin babies and 2 gold fish babies and 2 little fresh water fish…
    i use tap water for my fish using water conditioner.. i don’t have an oxygen pump.. my water are cloudy every time..
    and i don’t want to buy air pump…
    so what can i do……….
    and i am a starter …..

    • Scott @ Algone
      Scott @ Algone says:

      You don’t need an air pump and adding one won’t solve your cloudy aquarium water problem. It’s not unusual for a new tank to get cloudy water. In fact it’s a condition often referred to as ‘New Tank Syndrome‘. Generally cloudy water indicates increasing pollution inside the aquarium. This is best managed by feeding the fish sparingly. We recommend feeding just once a day and sparingly at that. Do not follow intersections on fish food packaging stating to feed 3 times a day however much the fish can eat in 2 – 5 minutes. This amount of food will wreak havoc on the fish tank.Feed sensibly as recommended above and also perform routine water changes every 2 weeks of about 15% of the water. Use a siphon to remove (vacuum) the gravel when extracting water for your water changes. If the cloudy water persists try using Algone. Algone is an excellent non-toxic water clarifier and helps clear up just about any type of cloudy aquarium water.

      Also see the following articles:
      Overfeeding Aquarium Fish
      Water Changes
      Clearing Cloudy Aquarium Water with Algone

  29. Nik L. says:

    I have a small 5gal tank with 4 small glofish and one cory cat. Tank has been running smoothly for 4 weeks now (one week with no fish, 3 with). I had the initial bacteria bloom during the second week which cleared up on it’s own in about 2-3 days. I hadn’t had a tank in a few years but knew this was normal for a new tank.

    I left on Friday and put just a few (maybe 3) shrimp pellets in for them to nibble on over the weekend. When I came back this morning, my tank is milky cloudy again and looks like another bacterial bloom. Is this normal? I don’t remember two occurrences of it in my old tank so this second one took me aback slightly.

    Is Algone a good suggestion to remedy this or is this also somewhat normal for fairly new tanks?

    Also, if I buy the Algone, where in my small Whisper filter should it be placed?

    • Scott @ Algone
      Scott @ Algone says:

      It sounds like your tank is still in the process of balancing itself. Bacterial blooms usually aren’t a health concern for your fish so it should be safe to wait it out. If you start to notice your fish gasping for air at the water surface however, you should take fast action with a 15 – 20% water change. Be sure to feed very sparingly during the bacterial bloom. Too much organic matter entering the tank will only complicate matters.
      Algone can certainly help with bacterial blooms as well. Algone gently aides in achieving biological balance in the aquarium. Algone pouches are thin and only about the size of a credit card, so placement in most filters isn’t difficult. If you don’t have enough space in your filter, Algone can also be placed directly in the water. Just make sure to secure it so it remains submerged, and also try to place it near the filters return for maximum water flow around the pouch. A veggie clip is very helpful with this.

      • Nik L. says:

        Oh awesome! I went ahead and ordered the Algone in the event I need it. Thank you SO much! I’ll try to slide it in with the filter cartridge. I appreciate your quick response!

  30. Fred Sponheimer says:

    i have a 3 month old aquarium and have taken my water for testing after the tank became cloudy! The fish store tested my water and found no problems but my tank is till cloudy! I have tried a partial water change but no help , i have also started feeding less ! How long should i wait for another course of action and what would that be?

    HELP

    • Thilo @ Algone
      Thilo @ Algone says:

      Three months in, the aquarium is still finding its balance, The exact time frame depends on maintenance, fish or plant additions, and changes.

      There are three major variations of cloudiness. Green, milky white, and yellowish. Green is and algae bloom, white a bacteria bloom and the yellowish discoloration indicates soft water with a high plant density or driftwood. For the latter, activated carbon will solve the issue.

      For green or white, the causes are similar, and I am generalizing. Excess waste by the form of overstocking or overfeeding. Reduce either one. Feed every other day whatever the fish can consume in less than one minute. Refrain from large water changes. 10% weekly preferably 20% every other week will do. Vacuum part of the substrate at each water change. Discontinue fertilizers, bacteria treatments, conditioners with bacteria etc.

      Algone will remove dissolved organics which are fueling either cloudiness. This shortens the time frame for the aquarium to biologically re- balance. If you follow the above, it is just a matter of time and patience.

  31. Callie says:

    I cleaned out my goldfish tank maybe a month or so ago. Since then, it has become very cloudy and we even bought a new filter system. No such luck. Could it be from using tap water to clean the tank instead of distilled? Or from replacing everything in the tank? It’s a 10 gallon tank and I have an 8 year old fish that I’m worried about. What should I do?

    • Scott @ Algone
      Scott @ Algone says:

      If your aquarium was completely cleaned out, you are probably experiencing ‘New Tank Syndrome‘.

      Cloudy water isn’t usually a concern for fish health. You should check for ammonia and nitrite however. Both should be undetectable as they inflame the gills of fish making it difficult for them to breath. Prolonged exposure can be lethal. One visual indicator of this would be the fish gasping for air at the water surface.

      Other then that, make sure you don’t overfeed and you keep up with regular water changes, nothing too large though as that can lead imbalances. Also consider Algone for ammonia, nitrite and nitrate removal as well as clarifying the water.

  32. Jenn says:

    To answer your questions. Its kind of a milky white. Fish get a pinch of food in the morning and i crumble some tubifex worm cube in the evening for them. They eat all the food. Plus the plecostamus gets an algae tablet in the evening(which he devours). The fish have been getting this much food for as long as I had them. Had them in a 20 gallon for 2 years prior to getting the 30. Water changes are about 10%.
    tank consists of 6 neon tetras, 2 black tetras, 2 dwarf gouramis and a plecostamus. My other 30 consists of similar fish and its crystal clear. Both tanks are in the same area of my house. Within about 5 feet of each other.
    Water has been tested and everything looks fine. I tested it and also took a sample to two different fish supply stores hopeing someone could figure out the mystery. Water in cloudy tank srems to clear up after a water change, but the next day its cloudy again.

    • Scott @ Algone
      Scott @ Algone says:

      It certainly sounds like a bacteria bloom. I would consider cutting back on the amount of food. We generally recommend feeding once daily and sparingly at that. Fish have a very slow digestive metabolism and therefore don’t require much food. Additionally they are “grazers” and there’s always something available in the tank, whether it’s food settled in the gravel or small amounts of algae growing on ornaments or the glass.
      Also consider trying Algone. Algone balances the aquarium resulting in sparkling clear water. Algone can be used as a clarifier and at regular maintenance intervals, thus preventing the tank from becoming cloudy. Learn more here.
      I’m sorry I can’t offer any big new revelation but as stated above I would certainly start with adjusting the amount fed. Even when all the food is eaten, additional waste is created as fish excrement increases.

  33. Jenn says:

    Alright new tank set up almost a month ago. Water still cloudy. Its a 30 gallon. Same fish came out of a 20 gallon, just wanted more room for my plecostamus. 20 gallon was crystal clear. Fish not being over fed.. They are getting exactly what they got in the 20. Gravel has been vacumed. Same gravel came out of the 20. Plus added some extra well washed gravel. No new decorations.. Same ones from 20 gallon. Doing weekly water changes. Water seems to clear up for a day and than goes super cloudy.
    I also have another 30 (set up 3 days after first tank with all new fish, recycled gravel from an old tank and old decorations) and a 10 (nothing new and set up same day as first 30) both are crystal clear. Whats with the cloudy tank any suggestions.

    • Scott @ Algone
      Scott @ Algone says:

      Is it a whitish or green cloudiness? Also, how much water are you changing each week? Also, can you be more specific about how much you feed your fish?

      Clearly there’s an ongoing imbalance in the tank. After almost a month, the tank should be fully cycled and balanced especially since you spiked it with your existing gravel.

  34. Vanessa Vercoe says:

    I set up a 65 gallon aquarium 5 days ago and two days ago I had massive cloudy water I changed about 20% of the water and used Prime during my water change the temperature of my water is 82 degrees because I have angels I’m using a 75 gallon aquaclear filter my substrate is a combination of a base layer of eco complete 40 pounds of Echo complete and and 60 pounds of aquarium gravel. I set up the tank and let it run for about 36 hours before adding my fish and 24 hours after adding my fish the water became cloudy. I ordered some aquatic plants I’m wondering if it’s okay to plant my plants in this cloudy water. Also I also ordered air stones to add oxygen to the water. Do you recommend dose in the tank with clarify

    • Scott @ Algone
      Scott @ Algone says:

      Hello Venessa! Cloudy water in a new aquarium is very common. It’s not usually something that’s harmful to your fish. If it’s not floating particles from the substrate, which usually settle within 24 hours, it’s likely a bacterial bloom. During the breaking in phase of a new aquarium, beneficial bacteria establish in the tank and can cloud the water if they’re present in over-abundance. This should clear up fairly quick on it’s own. Resist making big water changes with good intentions. Usually this will only throw the tank further out of balance.

      Personally I would not plant my tank until after it has fully cycled (broken in) which can take around 4 weeks after initial setup.

      Check these articles for more information:

      The Nitrogen Cycle
      Biological Filtration
      New Tank Syndrome
      First Aquarium

  35. Nova says:

    Help, help, help, help, help!
    I set up a new tropical 54L tank 6 weeks ago and am still getting cloudy water! I currently have half a dozen Neon Tetras and use Tapsafe and Stability when doing a weekly 15L water change. I get my water tested every week at least from my local aquatic shop and they keep telling me the water is totally fine, but whenever I try to add a new fish (a Balloon Molly) it dies within hours. I thoroughly washed the gravel, ornaments etc. before setting the tank up and as far as I know, I’ve done everything possible but I still have this problem with my fish dying. I’m on the verge of giving up!!

    • Scott @ Algone
      Scott @ Algone says:

      Hello Nova,

      Sorry to hear you are struggling to clear your aquarium. I would discontinue using Stability. It is likely causing an over-abundance of nitrifying bacteria (the beneficial ones) which will make the water cloudy. Since your tank has been setup for 6 weeks now and your water tests are good, it’s safe to assume the tank has already successfully cycled, so there should no longer be a need for a product such as Stability.
      Just make sure to feed your fish moderately, and not to overcrowd the tank and you should be on your way to a healthy and clear aquarium.
      I hope this helps.

  36. Rosemarysammie says:

    My fish tank got cloudy overnight and I’m afraid of losing my fish. My fish tank was set up two days ago for my lyretail mollies. I have 3 and a sucker fish. It’s a 15 gallon tank and I’m using a double air pump. I used tap water but put the amount stated of aquarium salt and jungle brand start right. I have a few arrangements and gravel inside, I rinsed off everything before inserting. I also think I’ve been overfeeding them and I leave the light on 24/7. I’ve turned off the light and stopped feeding them for the day till I can fix this issue. Please help

    • Scott @ Algone
      Scott @ Algone says:

      This is a very common issue. Water often turns cloudy after first setting up an aquarium. If it’s not just free floating debris from the gravel, it usually is what is called a bacteria bloom. Beneficial bacteria need to establish in every new aquarium. This process is referred to as ‘cycling the tank’ and can take up to 4 – 6 weeks to complete. During this time, ammonia and nitrite will spike. Once those nutrients are undetectable after they have spiked, only nitrate should be measurable. Nitrate is the final nutrient left in the aquarium from the breakdown of organic waste such as fish food and fish excrement. When only nitrates are detectable, the cycling of the tank is complete.

      Bacteria imbalances during the cycling can lead to cloudy water. Generally this is no threat to fish life and it should clear up on its own. We do advise to feed sparingly throughout the cycling process. This will limit the amount of waste entering the tank and will allow for a more gentle break in of the aquarium.

      Please read more here:

      The Nitrogen Cycle
      What Causes Cloudy Aquarium Water

  37. Sarah says:

    I have a 5 gallon tank set up for my boys and have established fish in it and the water has remained crystal clear. Set up an aquarium for my girls its a 10 gallon and after 2 days the water became cloudy and has been that way for 5 days now there aren’t any fish in the new aquarium so I don’t know what could have caused the cloudiness. I did use glass gems/pebbles in the 5 gallon and aquarium rocks in the 10 gallon and I washed them thoroughly could the gravel still be causing it UK become cloudy with no fish?

    • Thilo @ Algone
      Thilo @ Algone says:

      New setups are not sterile and bacteria can grow rapidly. Bacteria can be found on anything, gravel, equipment, ornament etc. Especially heterotrophic bacteria (those do not need ammonia). These bacteria can double within 20 minutes and cause a discoloration lasting for days and weeks.
      Other causes could be commercial additives such as conditioners, bacteria starters and so on. Washing off the debris is important and can cause a discoloration of the water, but that might not be your prevalent case.

  38. Alex says:

    I have set up a 46 gallon bow front tank about 4 weeks ago. Running a fluval Aqua clear 70 with a air pump. When I first set up my tank I added quick start with stress coat as water conditioner and Api ph increaser to 8.2 as I put in African cichlids. For the first 3 weeks the tank was perfect and crystal clear. Towards the middle of the 3rd week the ammonia spiked to 4.0ppm I was able to get it down to 2.0ppm. Then the end of the 3rd week the ammonia spiked to 9.0ppm and the water turned to a very thick milkish cloudy. It got so bad I couldn’t even see the the fish or decoration. It has been a week tomorrow and it is still the same maybe just a bit litter where you can slightly see the decoration and fish littly. What can I do to clear it. I don’t want to lose any fish.

    • Thilo @ Algone
      Thilo @ Algone says:

      During the break in period of a new setup, bacteria will establish colonies. These “beneficial” bacteria break down waste and ammonia/ nitrites. This makes the water safe for the fish. The process is know as the nitrogen cycle. You can read all about it here: http://www.algone.com/the-aquarium-nitrogen-cycle
      In general, the water will clear up as the aquarium establishes itself. You need to make sure to reduce food intake, which reduces the amount of waste, and to increase the oxygen flow. Oxygen is required by bacteria and increasing oxygen reduces the risk of low oxygen levels which is detrimental to the fish.
      Keep an eye on the fish behavior. High ammonia makes fish lethargic, no appetite, and inflamed gills. In case the fish are acting normal without showing any signs of ammonia poisoning, you might have used an ammonia remover that reacts with the test kit, showing ammonia where in fact none is present.

  39. Amy Watkins says:

    I started a goldfish aquarium 30 days ago, I have bn doing weekly water changes and treating with dechlorinators and start zyme. On my last water change, I also changed filter, as was quite yucky looking. The water has bn cloudy now for 6days! I’m thinking its cycling over again as I did a boo boo changing filter ?

    • Scott @ Algone
      Scott @ Algone says:

      Changing the filter may have caused the cloudy water. Obviously filter changes are a periodic necessity, but you should always try to avoid making too many changes at once as this will severely disturb the biological balance of the aquarium. Using Start Zyme can also create cloudy water conditions in the fish tank. Any type of bacterial product added to the tank can lead to white cloudy water when the bacteria become too abundant. There is a chance of de-oxygenisation from this but usually it’s not a threat and the water should clear up on its own rather quickly. Definitely discontinue the use of the enzymes though.

      The other possibility is that you have a free-floating algae bloom. If the cloudy water is green, then you likely don’t have enough beneficial bacteria established. As nitrate accumulate in the tank because of the lack of bacteria, algae spores utilize this nitrate as a food source resulting in an algae outbreak. Green aquarium water is a free-floating algae bloom.

      In any case, only incremental adjustments are recommended. Also, take care not to overfeed as this introduces new pollutants into the aquarium. While experiencing cloudy aquarium water we generally recommend feeding only once every other day (sparingly).

      Also check out Algone. It’s a great product for restoring and balancing the biological balance in the aquarium. Algone removes excess nitrate among other things. We are celebrating 20 years of Algone in 2015! It’s truly become a hobbyist favorite in that time.

  40. Saradee Delcamp says:

    HELLO, I AM SETTING UP A 30 GAL TANK…I AM USING CITY WATER. I HAVE MY GRAVEL, THERMOMETER.
    2 PLASTIC PLANTS AND UNDERGROUND FILTER. NO FISH YET.. THE P.H IS 7.5….THE PROBLEM IS MY WATER IS CLOUDY…WHY IS IT CLOUDY AND WHAT CAN I DO. I WOULD APPREACIATE A RESPONCE…
    HAVE A GREAT DAY…THANKS

    • Scott @ Algone
      Scott @ Algone says:

      Sorry for the late reply to this! Hopefully your water has cleared up on its own by now. Cloudy water in a newly setup aquarium is usually caused by the following two things:

      1. There are still a lot of very fine free-floating particles from setting up the aquarium. Most of this type of cloudy water is from the substrate and should clear up in a few days tops. It’s a good idea to rinse the filters with luke warm water from time to time. A lot of the particles will get caught in the filter, and some will settle at the bottom of the tank.

      2. The cloudy aquarium water may be a bacterial bloom. This is quite common in a new tank and it should clear up on its own as well. Initially the imbalance in a new aquarium can cause good ‘nitrifying bacteria’ to reproduce at a faster then normal rate, producing a white cloudiness in the water. This should also clear up over a relatively short period of time.

      See this link for more information: http://www.algone.com/what-causes-milky-white-cloudy-aquarium-water

      Hope this helps!

    • severiano says:

      I am having the same issue what I would say go to petco take a sample of your water and they will point you in the right direction …..thank you for your time

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