Skip to Content

How To Treat A Molly Fish Prolapse!

The popularity of keeping mollies within the fish keeping hobby is on the rise again and more and more people are starting to add mollies and other live bearers to their tanks.

Due to mollies being such a beginner friendly fish, we constantly see people reaching out who are new to fish keeping with a range of questions with many people asking about how to treat a prolapse in their molly.

The easiest way to treat a prolapse in a molly is to give the fish an Epsom salt bath to encourage the prolapse to retreat back into the body of the fish.

The standard Epsom salt bath is once per day for ten minutes for seven days with a water to Epsom salt ratio of one tablespoon of Epsom salt to two gallons of water.

Depending on how bad the condition is in your molly you may need to get a stronger treatment for this method than regular Epsom salt.

Booking a video call with a veterinarian should be able to help you get a realistic idea of the chances of recovery of your fish as well as if you need a stronger treatment than Epsom salt to help your molly get better quickly.

What Is A Molly Fish Prolapse?

A prolapse in a molly is when the anus of the fish protrudes from the body of the fish with it being visible when you look at the fish.

The length of the prolapse depends on the severity but a prolapse of less than one millimeter is usually treatable with Epsom salt baths but anything over one millimeter can be very difficult to treat.

Although the majority of our readers will be keeping standard mollies, there are a number of rare color and patterns out there that some people choose to keep.

If you notice a prolapse in one of these mollies then we would highly recommend that you get professional advice from a vet as soon as possible due to the higher price tags for the fish.

Due to the relatively small size of mollies as far as fish go, it is usually easy to notice the condition in the early stages often making it very easy to treat quickly.

If you have a dark colored molly then it can be more difficult to notice the prolapse, especially if you don’t view your fish on a regular basis but you can usually still see that there is a problem from the silhouette of the fish.

Is It A Prolapse Or Internal Parasites?

It is very easy to accidentally misdiagnose internal or even external parasites on your molly as a prolapse and this is far more common than most people think.

Both internal camallanus worms and external flukes can sometimes appear to be a prolapse on a molly in certain situations so always confirm the problem prior to starting treatment.

With most colors of mollies, flues should be easy to identify if you have a close look at them while having a photo available to compare them to.

The problem is with camallanus worms and an actual prolapse as they can look very similar depending on when the camallanus worm last fed on the blood of your molly.

The easiest way to identify a camallanus worm is by its color as it will change from a pale to dark red after feeding.

You can usually get fenbendazole, levamisole or praziquantel from your veterinarian to treat the condition in your molly if you do think that it is actually camallanus worms rather than a prolapse with the worms often being easier to treat anyway.

Why Do Prolapses Happen In Molly Fish?

Most prolapses in mollies and other fish occur due to the fish being over-fed and ending up constipated.

Some mollies will end up having a prolapse due to having an internal infection and female mollies can prolapse when straining to give birth to their live young too.

More and more people are crossbreeding guppies with mollies to make muppies with this being a common cause of a prolapse in a female mollie when she gives birth but she can still prolapse when she gives birth to normal molly babies too.

Infections that are bad enough to cause a prolapse in your mollies will almost always have secondary symptoms making it relatively obvious that this is the cause while also usually being easy to treat with something like Melafix.

Overfeeding fish is very common, especially for beginners but fish keepers of all levels of experience are often overfeeding their fish.

This is why prolapses are so common in pet fish but thankfully, an Epsom salt bath is usually enough to treat the condition in the fish and prevent the prolapse from being able to get worse.

If the prolapse has been left to develop then you can sometimes fast your fish by reducing its food intake while you treat your molly for the condition but this will not always help.

How Do You Fix A Molly Fish Prolapse?

The majority of people are able to fix a prolapse in their molly with an Epsom salt bath provided that they catch the prolapse early enough before it is able to develop.

You can usually make a quick and easy Epsom salt bath for your molly by adding one tablespoon of Epsom salt to two gallons of water and bath your molly in it for around ten minutes once per day for a week.

If the prolapse on your molly is over one millimeter in length then this may not be enough to treat the condition with some people upping the frequency of the Epsom salt baths to two or three times per day lasting for fifteen minutes each.

This does usually increase the risk to your molly though to getting advice from a vet prior to trying to is probably worth it to make sure that it is the correct path to take.

This is because some veterinarian offices can have stronger treatments for treating prolapses in fish that may work better for more severe prolapses in your molly.

Not all veterinary offices will stock these as standard though as they can be risky and most people will just opt to go with an Epsom salt bath instead of the specialist treatments.

Is A Molly Fish Prolapse A Serious Problem?

If a prolapse in your molly is not treat quickly then it can develop to be a real problem that may get bad enough to cause serious health problems in your molly.

This is why you should begin treatment with your molly using Epsom salt baths as soon as you notice the prolapse in the fish as the longer the prolapse is in place, the more difficult it is to treat.

If the prolapse is less than one millimeter in length then the chances of your molly making a full recovery are much higher than if the prolapse is over one millimeter in length.

Some people choose to fast their fish while treating them for a prolapse too and many people believe that this can help treat the condition but in reality, it only really helps if the prolapse is due to constipation.


That brings our article going over how to treat a molly fish prolapse to an end. Although the process is relatively easy, we constantly see people new to keeping fish worry about making the Epsom salt baths to put their molly in but it really is easy. The thing to keep in mind that there is a risk to your molly with Epsom salt baths but the risk of the prolapse getting worse and causing serious health problems is much higher.