Overfeeding Fish Causes Cloudy Aquarium Water

Tropical freshwater aquarium with fish

What happens if I overfeed my aquarium fish?

Overfeeding is one of the most common mistakes made by fish keepers. The consequences of overfeeding may not be immediately clear. Unlike a dog or a cat, an overfed fish usually doesn’t show the typical signs that tip us off that a diet may be in order.

Recognizing the negative impact of overfeeding fish is a bit of a murky affair… literally! Often it isn’t until our aquarium is afflicted with cloudy water, green water, or excessive algae growth that we realize we have a problem. Understanding what caused these problems requires us to connect the dots. Too much food is the primary cause for accumulating organic waste in the fish tank. Beneficial bacteria break this waste down into ammonia, nitrite, and eventually nitrate through a process called the nitrogen cycle.

The end result of excessive organic waste, or overfeeding, is nutrient rich water which can cause any of the following:

  • Cloudy aquarium water
  • Green aquarium water
  • Excessive algae growth
  • Toxic aquarium water
  • Fish poisoning
  • Oxygen depletion

How much should I feed my aquarium fish?

The reality is that cold-blooded fish digest food over longer periods of time then mammals do. This should be considered when feeding. Fish simply don’t require three meals a day. In most cases feeding an amount the fish can eat in one minute, once per day is adequate. When our aquarium is out of balance due to the consequences of excessive waste as outlined above, we may even consider feeding only once every other day until the tank can be brought back into a healthy balance.

The bottom line

  • Remember that the nutritional requirements of fish vastly differ from ours.
  • Aquarium fish suffering from malnutrition due to a lack of food is virtually unheard of.
  • Fish suffering from the negative consequences of overfeeding, such as ammonia poisoning or oxygen depletion is not at all uncommon.

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Eric Sykes

I have five jack Dempsey small fish a one sicker fish and I put to much fish food in the tank about 2 days ago. The pellets have soften and are at the bottom of the tank. I removed what I can but there are still some floating food particles I assume. What should I do?

The best thing is to go in there with a siphon and remove as much as you can. There shouldn’t be an imminent threat, but problems will occur if the food is left to rot in the tank. This will result in nutrient spikes and can cause an algae outbreak due to poor water quality. I recommend siphoning every 2 – 3 days until you feel you’ve removed most of the extra food.


I have different varieties of fish such as Oscar, Silver shark, shark fish,Parrot Fish, Malavi, Sucker Fish, Green terror and all. How can I feed these different varieties. What kind of fish food I have to use. How many times to feed them and which is the best fish food I can use which is commonly available and cost effective. Did I use any other water treatment medicines for fish health. I have Jewel vision 180 tank with external filter Jbl e 1501 and also jewel internal filter. Still weekly water change is required or not. please have your expert… Read more »


Floating and sinking pellets and once in awhile some frozen food. Feed whatever the fish can eat within one minute. This is the daily ration. You can split the ration in half and feed twice a day if you so desire.There is no need for preemptive medication. For sick fish, always use medication that is specific to the disease. Water changes are essential 10-15% every other week will do.


My daughter dumped my entire thing of fish food in my aquarium. We have a bottom feeder shark, but he was dying and I removed him from the tank. We have a REALLY big tank and my husband has to clean it when he returns from work. I took our bottom feeder shark out he started to float on the top. When u removed him from the water, however, he started swimming around again. I have a black goldfish worth huge eyes and I cannot find him anywhere in my tank. I was attempting to remove the shark and then… Read more »

The fish food shouldn’t pose an immediate problem when it was dumped into the tank. The problems arise when too much is left to decay in the aquarium, inevitably resulting in ammonia, nitrite, and nitrate spikes. An algae outbreak is then also more likely to occur because of the high nutrient concentration.

Your best bet for finding your goldfish is to carefully remove any ornaments, decorations and plants in order to find the fish. Sorry, but I don’t know of an easier way of doing it.

Good luck with the tank. Hopefully it al works out.


What if the water is cloudy? What do I do then?

Please review the following articles related to cloudy aquarium water:

How to Clear Cloudy Aquarium Water
Cloudy Aquarium Water and Algone
What Causes White Cloudy Aquarium Water
The Secret to Crystal Clear Aquarium Water

Please also check out Algone Aquarium Water Clarifier & Nitrate Remover. Algone has become a staple for aquarium maintenance, water clarification, and nutrient control.


Do you just not feed the fish or something for your aquarium to clear up? Because you weren’t very clear on what to do.

Scott @ Algone

The idea is not to overfeed. Overfeeding pollutes the aquarium which produces nutrients including ammonia and nitrate. Nitrate is a natural fertilizer which can lead to algae growth in the form of green water. Our recommendation is to cut feeding to once every other day if you are experiencing green aquarium water or any other kind of algae growth. Using Algone to reduce nitrates will also help restore balance to the tank. Bottom-line is that feeding your fish the right amount of food is a matter of trial and error. Obviously you should never do anything too extreme when cutting… Read more »

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