Treating and Preventing White Stringy Poop in FishWhite fish poop is an issue that is more common than you think, though it doesn’t mean that it’s always there due to a disease. If you are observant of your fish and notice it right away, it will not lead to many problems either way.

If you find white fish poop on your fish or your tank, you should know what that white stringy stuff in fish tank is before you touch it. Keep on reading to understand this symptom better and learn to cure it properly as well.

What Is White Fish Poop?

White fish poop is a phenomenon that can happen if your fish hasn’t eaten food for a while or it is also proof that your fish has not digested its food properly. Whichever one is the case for your fish, we will help you understand all reasons behind it.

What Causes It?

Now, what causes the white string hanging from fish? To move things along, the fish’s gut is lined with mucus-producing cells. This helps the food slide along smoothly by acting as a lubricant.

This mucus is invisible when the fish is eating properly, but if the fish doesn’t get enough food, the mucus leaves the body as white strings!

This means it is completely normal sometimes to see your fish pooping long strings. It just means that the fish hasn’t eaten food in a while and is hungry. You shouldn’t ignore this sign and feed the fish as soon as possible, but it doesn’t mean that your fish has some serious disease.

Reasons for Fish Pooping White

You now know one of the biggest reasons that your fish might be pooping white is that it might have undigested food in its belly, or the fish simply hasn’t eaten yet. More rarely, though, there can be a more serious reason for white stringy stuff in fish tank. Let’s view those more serious reasons below.

  • Parasitic Infection

After immediately reading this, you might be really worried. However, you shouldn’t because this is a really rare case. It is only possible if the fish you own is wild-caught or has been in contact with a wild-caught fish.

One way to identify a parasite is if the poop of your fish moves around, especially against the current. It can be hard to see since their poop is very light and can seem to be moving on its own.

This is why you should take it out using a turkey baster and put it in a clear cup or plate to see if it still moves. If not, your fish pooping long strings is not as serious as you think.

These internal parasites can be either intestinal protozoa or intestinal worms. If the infection is internal protozoa, then it could be spironucleus or hexamite. If intestinal worms cause the infection, it could be tapeworms or roundworms. These can more rarely be also a result of dirty and infected objects introduced into the water.

However, as mentioned earlier, it is very rare. If your fish suffers from this, it is best first to separate the fish so it doesn’t infect others, and then take it to an aquatic doctor who will prescribe it with appropriate medicine or ointment. It is better to treat it as soon as possible.

  • Bacterial Infection

This is a more common cause of white string hanging from fish than parasitic infection. White poop is one symptom of this infection, although not always.

Bacterial infections like bloated stomach, swim bladder, dropsy, and rectal infections all cause white stringy poop. Observe your fish and if it seems to be suffering from these common infections, then cure it, and the white poop will go away.

Taking it to the vet is the best course of action, so you know which one of these bacterial infections may be the cause.

  • Preventing Bacterial Infection

Good water quality and not introducing new fish in the tank without quarantining them first will prevent this from occurring. This is a common cause of infection only if you don’t know how to care for the fish and do not provide the fish with appropriate water parameters. 

This is why having a water testing kit at all times is so essential. The testing kit will tell you immediately if anything is wrong with your water, and you can fix it before it can cause disease to your fish.

  • Non-Disease Reasons

The first reason could be this: If you prescribe medicine to your fish without it actually having the disease can be very bad for it in the long run. 

One of the most common reasons for non-disease stringy fish poop is stress. Stress can be caused by many things such as small tanks, inappropriate water conditions, violent tank mates, and an unhealthy diet.

All of these factors can contribute to your fish not wanting to eat food and resulting in this kind of poop. Stress is easy to cure as long as you realize the stress factor and fix it.

Even high levels of ammonia and chlorine can cause stress or some underlying digestive problem. If your diet has too much fiber or fat, it can be a reason for stress as this is a bad diet. Moreover, some medication and multivitamins can also lead to white stringy poop in your fish.

What Should Be Done To Cure White Fish Poop?

Well, first of all, you need to understand the underlying issue causing this poop consistency and color. Once that is done, you should then look for a proper cure for the disease or issue.

If the cause is some disease, like a parasitic or bacterial infection, you should immediately separate the fish from the rest of its tank mates and then take it to the vet. There the doctor will prescribe the appropriate medicine.

Stringy White Fish Poop Cases, Treatment and Prevention

You should do it as soon as possible as if you are too late it can kill the fish. You should also check the other fish in the tank because the chances are that they have also been infected.

However, if the cause is not a disease, then you won’t need medication. Try changing the fish’s diet and environmental conditions, like not having too much light in the tank.

Moreover, test your water using a water testing kit to ensure ammonia and chlorine levels are not high. Make sure to follow these steps until you find the reason. 

Making those small adjustments if it’s not a disease will immediately cure the white stringy poop disease. However, if it persists, then going to the wet might be a good idea. It will also help with your anxiety about the matter, and you will know for sure if your fish has some serious underlying issue or not.

What Does Normal Fish Poop Look Like?

Before getting started and finding the reason for white poop, you should know what normal poop should look like. The thing is, stringy fish poop is not a normal consistency that should be found.

If you have ever observed fish poop, you must be confused because there are so many colors of poop available. You might have seen green, brown, white, and even pink poop. The fact is that the poop of fish depends on what it eats and what the thing it eats looks like. 

It really can be any color. So, how do you know it is healthy poop?

People are indeed still confused about what color a healthy poop should look like. The general thing to remember is that the poop of fish should resemble the food that the fish eats. For example, if your fish eats mostly vegetables, the poop should be green, and if the fish eats flakes or bloodworms, the poop should be red in color.

Another thing to observe is the size and consistency of the poop. Usually, it is solid in inconsistency, so the fish pooping long strings is not normal. When removed, the poop sinks to the bottom of the tank, and it should never be more than half the size of your fish. 

Remember that the excretion can be a lot longer than usual when you overfeed your fish. Also, it does have a smell, just like most other poop in the world.

How Does a Fish Poop?

To know why your fish might have white stringy fish poop, you should know the mechanism of pooping of your fish. This is a lot similar to humans, but not all fish have the same mechanism as they are all unique.

First of all, the scientific name for fish poop is detritus. It stands for all the dead particles of organic material that are undissolved in the digestive system, so it gets excreted.

Just like most mammals, fish release detritus through their anus, which is at the end of their alimentary canal. When this alimentary canal is full, it pushes all the waste material out of the body of the fish.


White poop on fish is not a very serious reason unless you have not been taking care of the fish that well. It is best to take the fish to the vet regardless of the reason to find out what is wrong with it and help heal your fish.

Moreover, here are the crucial points from this article that will come in handy whenever you want the short summary of everything we’ve talked about in this article:

  • Stringy white poop is not the normal consistency of fish excretion
  • Fish have various colors of poop depending on what their diet is
  • Usually, white poop is caused by the fish not getting enough food, which could be due to many reasons
  • It could also be due to parasitic or bacterial infection
  • In case of infection, going to the vet is a good option

So, if the fish are pooping white, you need to take proper care of the fish and take necessary remedies for it by using our advice in our post. 

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