What Eats Fish Poop? Everything You Need to Know About Fish Poop

Fish poop is always an eyesore, and it often dulls the beauty of your aquarium tank. Your first idea for removing fish poop from your tank may be to get a fish, plant, or other living organisms that can eat fish poop.

Unfortunately, it’s not that easy because no living organism has been confirmed to eat fish poop for nutrition. So, how then do you remove fish poop from your tank? And how much harm does fish poop cause to your aquarium?

This guide will tell you everything you need to know about fish poop, including what makes it inedible, how to reduce it, and the safety risks that come with it. 

Let’s get started.

Why is Fish Poop Uneatable?

Products left in poop are mostly waste, so there is no good part in providing nutrients to living organisms. However, there are some scenarios where some fishes eat poop or nibble on it.

Most times, this happens unintentionally. People say some fish species like Pleco and Corydoras eat poop, but there is no conclusive evidence that they do. 

Even if some fishes eat poop, they would still need to be fed like other fishes and produce their poop. This will ultimately not solve the fish poop problem in your tank.

Is Fish Poop Good for Aquarium Plants?

Contrary to common misconceptions, fish poop isn’t good for aquarium plants. While you might be thinking that they can act just like other excrements and be a source of manure for your plants, that’s not the case.

Although the nitrogen in poop is excellent for plants, the nitrogen produced from your fish poop does not get to your plants directly.

In the tank water, there is a chance that the nitrogen will bond with hydrogen molecules to produce ammonia, which is lethal to fishes and aquatic plants. Ammonia will destabilize the respiration process and mess up the ecosystem in your tank.

If you have gravel or a thick layer of pebbles in your tank overlaying the top of the soil substrate, the fish poop will not be able to reach the soil.

Most aquatic plants grow on the soil, and only a few grow on the pebbles’ hard surface. This makes it  hard for the poop to reach the root of plants, so keeping it in your tank will not do you any good. 

What is the Difference Between Fish Poop and Waste? 

Often, people assume fish poop and waste are the same and can be used interchangeably. This notion is wrong. Fish waste encompasses all the types of waste materials you can find in your tank, usually classified under inorganic waste and organic waste. Fish poop is an example of organic waste.

Organic Waste

Organic waste is gotten from any living organism or anything that can decompose. Often, you don’t need to dispose of them yourself as they’re mostly perishable and will decompose in an environment that allows it. Organic waste typically decomposes into the soil or water in some cases. 

This is the main source of ammonia in a fish tank after it has been broken down. The nitrogen cycle would be impossible without it, as ammonia kickstarts the oxidation process that produces the less toxic nitrates. Examples of organic matter include fish poop, dead plant matter, decaying organic compounds, and algae.

Unlike fish poop that can dissolve into the soil of your tank over time, fish food pellets cannot undergo a natural organic cycle. That will dissolve them into the water or soil of the tank. Other organic waste materials that could fall into an open tank are dust particles, small insects, pollen, etc. (ref 1)

Inorganic Waste

Inorganic waste materials cannot decompose on their own. They need an external influence or stimuli to start the decomposition process or get rid of them entirely.

Often, these items do not mix with the water or soil in your tank, and even when they do, they will not decompose fully. Over time these materials will negatively affect your tank’s ecosystem and become a danger to your fishes.

A lot of the inorganic waste in your tank enters from the outside. Ping pong balls and small pieces of paper are some of the most common inorganic wastes you’ll find in tanks.

These items do not decompose and will probably be there longer than your fishes – and you! The best way to take care of inorganic waste is to remove them from your tank.

How Else to Get Rid of Fish Poop in Tank?

Since finding a living organism to eat the poop in your tank isn’t possible. The other way to reduce fish poop in your tank is by cleaning it and not overfeeding your fish.

Cleaning the tank

Cleaning your tank will help get rid of all; the fish poop and other waste materials in your tank. It keeps your aquarium looking beautiful and keeps the ecosystem thriving.

Why Do You Need to Clean the Tank of Fish Poop?

Clear Viewing: It’s no fun to look at an aquarium tank that is murky with fish poop littered all over the ground and walls covered with algae and slime. It can be difficult to see your fish and plants’ color, making it even difficult to recognize them. In some extreme cases, they also give off foul odors.

Health: A dirty tank is harmful to the health of your fishes. They often harbor viruses, bacteria, fungus, and other threats that could be lethal to your fish. There tank’s pH will also be imbalanced, which could further stress your fishes were putting them at risk of death.

Function: A fish tank filled with floating debris and excessive waste can put serious pressure on the pump, filter, and other essential mechanisms in the tank. Over time this could make the mechanisms sluggish, clogged, or even stop working entirely. If they stop working, the environment will become dangerous and deadly for the fish quickly.

Top 5 Ways to Keep Your Tank Clean

Regularly Change the Water: 

Changing your water according to a schedule can go a long way in keeping the waste in your tank minimal. A water change will remove the dirty spent water and give the fishes access to freshwater. Generally, to keep your fish comfortable and still keep the conditions of the water balanced, you should change only 10-20% of the water every 2-3 weeks.

Don’t Overpopulate Your Tank: 

Small size tanks often get dirty faster, especially if the fishes in the tank are too big for too much for it. If there is enough space in the tank for your fishes and plants, the fishes will be less stressed. Also, the filters will work much better at keeping the tank clean and clear of any impurities. (ref. 2)

Select your Filter carefully: 

Filters help remove the waste and debris in your tank to ensure it stays clean and healthy for your fishes. You must select a filter that can handle the needs of your tank. There is no point in buying an expensive filter that will be excessively stronger than your aquarium setup.

Trim your Plants: 

If you have live plants in your aquarium, there is a chance that they may begin to decay or turn brown. Over time they may fall off and dirty the tank, making it look dirty. It is always better to spot this early on so you can trim the dead bits away and remove them from the tank.

Vacuum the Gravel: 

Fish poop, leftover food, dead plants, and other debris settle down to the bottom of the tank, making it hard to reach. You can set a schedule to use your gravel vacuum every week to remove this debris from the tank’s bottom and keep it clean.

Stop Overfeeding Your Fish

Giving your fishes more than enough food will leave them overfed and leave many leftovers in the tank.

Overfed fishes tend to produce more poop, and if you keep overfeeding them, your tank will not be able to keep up with converting the poop to nitrites. It will create a lot of ammonia, which will stress out your fishes and make them sick.

How to Avoid Overfeeding Your Fishes

Use a Feeding Schedule: 

Set out a time when you will give your fishes food, not just anytime or when you feel like it.

On average, feeding your fishes twice daily is sufficient and should provide them with all the nutrients they need to stay nourished.

You can also decide to give them food more frequently but in smaller portions, because fishes are always foraging and nibbling through the day.

Feed them only what they need: 

Observe your fishes while you feed them, so you know when you are giving them more food than they need. Add a small amount of food and see how long it takes for them to finish it.

If they finish it fast within a few minutes, add a little more. Just make sure that you only feed them what they can finish in 4-5 minutes.


Should You leave fish poop in the tank? 

Fish poop will float around inside your tank before it settles down at the bottom. Sometimes fish eat it while flowing, but they eventually spit it out when they realize it is not food. 

Fish poop will decompose over time to form ammonia and then break down further to form nitrate. Aquatic plants in your tank will consume the ammonia and nitrate as it is beneficial to them thanks to the Nitrogen cycle. 

If you leave fish poop in a tank where there is no gravel/soil substrate to mix with, the excrements will slowly but surely settle to the bottom of the tank. If you leave this in your tank, the poop will become a pungent and toxic smell in your tank.

This could lead to an increase in temperature and alterations to the tank’s pH levels, totally putting your tank’s ecosystem in disarray.

What color is fish poop? 

The color of fish poop usually is dependent on the fish species and the type of diet the fish is eating.

Color pigments from the food you give your fishes can dissolve in the fishes’ intestine. Their poop will have a color similar to the color of the food they eat.

Healthy fish poop should have a slightly brown color like sand or the color of food it is being fed. A brownish tinge in your tank water usually signifies diarrhea caused by low-quality food with lots of toxins.

If you notice a white-colored poop in your tank, it could be a sign of internal infection, and you should act on it fast. Possible steps you can take is to change its diet or have your fish checked out.

How will you know when fish poop is too much in the tank? 

Fish poop releases ammonia into the water. 

The natural nitrogen cycle in the tank should help reduce the ammonia content. Still, but if the poop becomes too much, the ammonia produced is excessive. The natural cycle will not be enough.

High levels of ammonia in a tank can destabilize the already established ecosystem, so it’s best to get ahead of it before you start seeing any signs. (ref. 3)

You shouldn’t wait until fish poop becomes too much in the tank because, at that point, the damage might already be done. As a regular practice, clean the tank regularly so that poop does not accumulate. 


Keeping fishes doesn’t always have to be a pretty job. Sometimes you need to get your hands dirty. Especially considering you have to make sure their poop in the tank is kept in check, it does not adversely affect their health.

As explained, since using fishes or other organisms to eat fish poop isn’t a reliable method, you have to use different methods to handle the poop. The best way to keep the fish poop in your tank at a minimal level is regular cleaning and monitoring the amount of food you feed your fishes. 

[tcb-script type=”application/ld+json”]{ “@context”: “https://schema.org”, “@type”: “BlogPosting”, “mainEntityOfPage”: { “@type”: “WebPage”, “@id”: “https://www.snugaquarium.net/what-eats-fish-poop/” }, “headline”: “What Eats Fish Poop? Everything You Need to Know About Fish Poop”, “description”: “Fish poop is always an eyesore, and it often dulls the beauty of your aquarium tank. Your first idea for removing fish poop from your tank may be to get a fish, plant, or other living organisms that can eat fish poop.Unfortunately, it’s not that easy because no living organism has been confirmed to eat fish poop for nutrition. So, how then do you remove fish poop from your tank? And how much harm does fish poop cause to your aquarium?This guide will tell you everything you need to know about fish poop, including what makes it inedible, how to reduce it, and the safety risks that come with it. Let’s get started.”,”keywords”: ‘’What Eats Fish Poop’’, ‘’Is Fish Poop Good for Aquarium Plants?”, ‘’What is the Difference Between Fish Poop and Waste?’’, ‘’Should You Leave Fish Poop In The Tank?’’, ‘’How to get rid of fish poop in tank’’ “image”: “”, “author”: { “@type”: “Organization”, “name”: “Eric T. Toth” }, “publisher”: { “@type”: “Organization”, “name”: “Snug Aquarium”,”sameAs”: [ “https://www.facebook.com/SnugAquarium”, “https://www.instagram.com/SnugAquarium”, “https://twitter.com/snugAquarium”, “http://www.pinterest.com/snugAquarium” ], “logo”: { “@type”: “ImageObject”, “url”: “https://www.snugaquarium.net/wp-content/uploads/2021/01/SnugAquarium.jpg”, “width”:50 , “height”:50 } }, “datePublished”: “2021-02-24”, “dateModified”: “2021-02-24”}[/tcb-script]

Enjoy this? Like and share for later…

Scroll to Top