Flowerhorn Intestine Coming Out – Bulging Anus Cause

Disclosure: I may earn a commission when you purchase through my affiliate links. As an Amazon Associate I earn from qualifying purchases. – read more

As a semi-experienced fish keeper, a few things will probably take you by surprise in terms of fish disorders.

The usually Ich, bloating, swim bladder disease, and various parasitic and bacterial infections have most likely already become the norm. But what about less common disorders?

Flowerhorns will sometimes experience prolapse which isn’t limited to this species only. Other fish will have the same problem which can even worry more experienced aquarists.

But what is causing the fish’s anus to protrude, is it contagious, and can it kill the victim? Let’s assess the situation to shed light on this concerning issue.

Causes of Bulging Anus in Flowerhorn

There are several causes for a prolapsed anus in flowerhorns, some of which may be more severe than others. An interesting aspect is that flowerhorns are more prone to experiencing a bulging anus than other fish species.

This is partly due to their more sensitive digestive system and the fact that they are more prone to some conditions than others.

That being said, if your flowerhorn experiences a bulging anus, consider the following causes:

  • Constipation – Not all flowerhorns that experience constipation will also have a bulging anus, but some will. Constipation is often the result of overfeeding and is especially frequent in cichlids like flowerhorns due to their rather ineffective digestive system. The problem with constipation is that a bulging anus is probably the least severe effect. Compaction is deadlier, causing an intestinal clog due to the waste drying out and blocking the exit.
  • Improper diets – The same effect occurs due to inadequate diets, leading flowerhorns to experience often deadly health problems. In typical cichlid fashion, flowerhorns require a lot of protein in their diets, but not enough to affect their digestive system. Cichlid fry will do just fine, with about 60% of their meals consisting of animal protein. Adults, however, only require around 40%. Any significant surplus will affect the digestive system since flowerhorns require fibers and plant-sourced vitamins and minerals as well. This is a common issue among flowerhorn keepers, especially novice ones who tend to provide them with a carnivorous diet.
  • Parasitic infections – Some intestinal parasites will also cause a prolapsed anus in the more severe cases. However, the good news is that if your flowerhorn experiences a parasitic infestation, you should be able to tell way before the prolapse. The most common symptom of parasitic infections is the seemingly unexplained bloating, combined with a variety of behavioral changes like lack of appetite, lethargy, increased aggression, hiding behavior, and more.
  • Getting ready to lay eggs – This means that only female flowerhorns will experience this condition. It also means that it’s not really a disorder but a natural effect of getting close to delivering the eggs. It’s pretty easy to tell if that’s the case, especially if you’ve already determined that your female was gravid, to begin with.
  • Other conditionsDropsy sometimes causes this effect, although it also causes bloating, pale feces, swelling eyes, clamped fins, and others. The same goes for Ich or any digestive problem, whether it’s viral or not.

All these potential causes show the urgency of an immediate and accurate diagnosis since this is the only way to ensure early treatment.

Without that, many conditions will aggravate fast, killing your flowerhorn and potentially spreading to other tank inhabitants as well.

How to Treat Bulging Anus in Flowerhorn?

There are several treatment options for a bulging anus, depending on the underlying cause:

  • Epsom salt – This is the common name of the compound magnesium sulfate. Epsom salt is useful for treating dropsy, swim bladder disease, and even constipation in the right amounts. Make sure you speak to your fish vet before using it to make sure you’re using it as intended.
  • Antibiotics – These are useful for addressing dropsy, Ich, and any other parasitic or bacterial infections that could jeopardize your flowerhorn’s life. Like with Epsom salt, speaking to a professional beforehand is crucial since several medications and antibiotics are available, each with its own effects.
  • Address the fish’s diet – If the cause of the bulging anus is food-related, approach the treatment from that perspective. Check to see whether your fish’s diet is within the acceptable parameters. Adjust how much protein your flowerhorn is getting and look for any signs of vitamin or mineral deficiencies. You should also check for signs of constipation. Each issue should be tackled accordingly; in the case of constipation, allowing your flowerhorn a 2-3-day fast period is usually enough to address the problem. When it comes to any nutrient deficiencies, the solution is pretty much self-explanatory.
  • Adjust the water quality – Your flowerhorn will require impeccable water conditions throughout the treatment process. Keep the water temperature around 80-82 F and perform daily partial water changes to prevent any ammonia or nitrite buildup. This is usually enough to boost the fish’s immune system and counter the disorder naturally.
  • Surgical intervention – Sometimes, surgical intervention might be necessary, but only an expert vet can recommend that after assessing your fish’s condition. In this case, diagnosing and treating the condition in its early phases is more likely to prove fruitful.

When it comes to treating a bulging anus, I recommend using a hospital tank to quarantine the fish for the entire duration of the treatment.

This allows you better control over the fish’s environment and water quality and will protect the main tank’s environment in case you’re using medication.

How Long Can Flowerhorn Live with Bulging Anus?

The answer depends on the condition’s triggers. If it’s parasitic in nature, it also depends on the type of parasite and how strong the fish’s immune system is.

No matter the condition’s underlying causes, leaving it untreated is bound to aggravate it fast. In some cases, your flowerhorn may only have days to live.

In others, they might live longer, provided the condition isn’t as serious and will aggravate gradually instead of suddenly.

That being said, it’s never wise to ignore a bulging anus, no matter how innocuous the symptom might be. Severe, deadly disorders often have small beginnings, and it’s small symptoms like these that sound the alarm signal.

What to Feed Flowerhorn When It Has Its Intestine Out?

This depends on the condition’s causes. If the flowerhorn experiences a bulging anus due to constipation, you shouldn’t feed the fish anything at all.

Keep the fish in a fasting state for about 2-3 days to allow its digestive system to recover. This is the best treatment approach you can ensure.

After the fasting period is complete, provide the flowerhorn with boiled and skinned peas for a surplus of fiber to eliminate all traces of waste and cleanse the intestine.

Other than that, your fish should get a diverse and nutritious diet during the treatment, provided the vet recommends otherwise.

Generally speaking, providing your flowerhorn with a balanced diet will increase the treatment’s effectiveness as it will help the fish’s body fight the disorder.

Is Bulging Anus Contagious?

It depends on its causes. If it’s dropsy, yes, it is contagious. The same goes for Ich and swim bladder syndrome, provided those conditions are viral in nature, which isn’t always the case.

The primary problem here is that you can never tell for sure, not without taking your fish through a more in-depth diagnosis process. And you can’t risk keeping the sick fish in the main tank during that time.

I suggest quarantining the flowerhorn in a different aquarium, preferably large enough to accommodate the fish. Ensure optimal water parameters and stable temperatures and provide the flowerhorn with a nutritious diet until you figure out the condition’s causes.

This approach will eliminate the risk of other fish contracting the same disease if they haven’t already.


Flowerhorns are quite prone to experiencing a bulging anus which isn’t always a cause of concern. But, since you can never tell by default, I recommend resorting to in-depth assessment and diagnosis instead of relying on gut feelings and wishful thinking.

Nothing beats early treatment when it comes to providing your flowerhorn with the best chance at recovery.

Author Image Fabian
I’m Fabian, aquarium fish breeder and founder of this website. I’ve been keeping fish, since I was a kid. On this blog, I share a lot of information about the aquarium hobby and various fish species that I like. Please leave a comment if you have any question.
Leave a Comment

Your email address will not be published. Required fields are marked *