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3 Common Causes Of Red Fish Poop!

After seeing a spike in the number of worried fish keepers reaching out panicking due to noticing red fish poop in their aquariums, we have decided to publish our own dedicated article on the most common causes of red fish poop.

We totally understand why so many people are panicking when they see red poop as they usually see red and think blood!

Thankfully though, that is very rarely the case in most fish and two of the three most common causes of red fish poop are simply down to diet with the third being very easy to treat.

We will be going over how you are able to diagnose each of the three causes as well as how you are able to treat them as quickly as possible.

This should make it very easy for even a beginner fish keeper to quickly workout the cause of the red fish poop.

We often see some more experienced fish keepers struggling to workout why their pet fish has red poop so even if you have been keeping fish for years, we hope that our article is able to help you.

Red Flake Fish Food

The most common cause of red fish poop by far is the red flakes in fish food. Most fish species have a very short digestive track so they are unable to process the red dye in the flakes prior to poopig it out.

This results in red poop and a large number of unnecessarily worried fish keepers.

If you feed your pet fish tropical flakes then this does tend to be more common than if you are using other types of flakes but it can commonly happen with all types of fish food.

You are able to confirm the diagnoses in your fish by trying to remove the red flakes from their food but this is usually more hassle than its actually worth.

You can usually just switch out the regular flake food of your fish to a pellet fish food and observe if the fish in your tank still poop red or if it turns to a normal brown.

The majority of people will find that this is all it tasks to stop red fish poop allowing you to put your mind at ease and relax knowing that there is no serious health issue with your fish.

Camallanus Worms

Although rare and not technically poop, a parasite infection in your fish, usually camallanus worms can give the appearance of red fish poop but it is actually the worms hanging out of your fish.

We know that this is unsightly but thankfully, it is very easy to treat the majority of the common parasitic infections in most types of fish.

One of the most common treatments that will work on most parasites that can be infecting your pet fish is to use No products found..

Not only is it cheap, effective, and very easy to use but it has an excellent reputation within the community for treating parasites in both freshwater and saltwater fish.

Your fish will usually lose weight quickly and appear to be lethargic if this is the cause of the red poop in your fish. Please note that after using a parasite treatment in your fish, it will often look like your fishest poop turns black for a few days prior to returning to normal.

This is the dead parasites being expelled from your fishes digestive system and it is totally normal and to be expected.

Bloodworm Skins

Although very rare, some fish who have bloodworms in their diet can end up pooping out their skins or husks with their poop having a dark red look to it.

This does not occur in all fish species and usually needs a few other things to be occurring in the diet of the fish but it is nothing to worry about.

You are able to test if this is the cause of the red fish poop by not feeding your fish bloodworms for a few days and just waiting to see what happens.

One thing that you should note is that freeze dried bloodworms can still have this effect even though they are brown in color rather than red.

This is due to the red color of the bloodworm husk returning when the husk is hydrated. We have seen a number of people who fed their pet fish bloodworms be thrown off by this when their issue was infact the bloodworms.

Thankfully, this is not a serious issue and is totally natural so you can continue to feed your fish bloodworms as a part of their diet.


That brings our article going over the three main causes of red fish poop as well as how you are able to diagnose each one as well as treat it. As we mentioned back at the start of the article, two of the causes are totally harmless and are due to the diet of your fish with the third one being very easy to treat for most people so there is nothing to worry about in most cases if you do notice red fish poop in your aquarium.