Skip to Content

Clownfish Disease (Brooklynella): The Cause, Signs, & Treatment

Clownfish Disease (Brooklynella): The Cause, Signs, & Treatment

Share this post:

This post is written to the author's best knowledge and is not intended to be used in place of veterinary advice. In addition, this post may contain affiliate links. As an Amazon Associate I earn from qualifying purchases.

Generally, clownfish are considered to be fairly easy to take care of. Most enthusiasts will tell you that clownfish are some of the easiest saltwater fish for beginners to care for.

This doesn’t mean that there aren’t significant problems that you need to be aware of. For example, clownfish are susceptible to certain types of diseases.

One such disease is commonly referred to as clownfish disease. It’s also known as Brooklynella disease.

This is a very serious condition that could easily kill your fish. What is this disease and what do you need to know about it to protect your fish in your aquarium?

Read on to learn everything that you need to know about clownfish disease. It’ll help you to have a better experience when caring for these fish.

What Is Brooklynella Disease?

Brooklynella disease is actually a type of parasitic infection. Clownfish and other types of marine fish can become infected by a parasite known as Brooklynella hostilis.

This parasite specifically attacks the gills of marine fish. It makes it so that the fish aren’t able to breathe properly.

Sadly, this is a condition that can easily lead to the death of clownfish or other marine fish. If you notice any signs of this disease, then you’re going to need to take action right away.

Typically, this disease is closely associated with clownfish. That is part of the reason why it’s colloquially called clownfish disease.

It’s also commonly associated with other types of damselfish. The parasites that are responsible for the disease are not picky with the types of hosts that they choose, though.

These parasites require a host fish to be able to survive. They’ve been known to infect various types of angelfish, wrasses, tangs, and even seahorses.

The parasites themselves are shaped like kidney beans. They’re covered in cilia and they’re microscopic.

Being microscopic doesn’t keep them from being able to do real damage to your clownfish, though. If you want your fish to survive this situation, then you’ll need to be a very proactive fish owner.

What Are the Symptoms?

Clownfish Near Objects in the Tank

There are a large number of different symptoms of Brooklynella disease to look out for. One of the first things that you might notice will be the fish trying to scrape up against objects in the fish tank.

You might see your clownfish will try to rub itself against rocks or other objects. This is in an effort to remove the attached parasites because they’re causing breathing issues.

The parasites are going to attack the gills first, and then this disease might wind up spreading beyond the gills. You’ll likely see that your clownfish will be gasping for air when they are experiencing this condition.

Sometimes the clownfish might try to go to the top of the tank in an attempt to get more oxygen. Its gills are going to be clogged with mucus and breathing is going to become quite difficult as things get worse.

Your clownfish is going to start acting a lot differently during this time. For instance, it’s going to become very lethargic and it might even stop eating entirely.

This is certainly worrisome, but sadly the symptoms don’t stop there. You’re also going to notice the color of the fish will start to fade a bit.

Often, fish that have been infected by these parasites will start becoming excessively slimy. It makes fish produce a lot of slime, and you might even be able to visibly notice white mucus covering the body.

Generally, the mucus will start at the head of the fish, and it will then progress down the body. Skin lesions might start to appear when the infection is advanced.

The skin lesions are very dangerous because they can lead to secondary infections. If the fish doesn’t get the right treatment, then the skin lesions could easily cause the fish to die due to being infected in various locations.

You might see that the fish will experience fin rot due to secondary infections. Needless to say, this is not a parasitic infection that can be taken lightly.

What Causes Brooklynella Disease?

So what is it that causes this disease in the first place? If you have a better idea of what causes the infection, then it’ll be simpler to try to avoid having this happen again.

The only thing that directly causes Brooklynella disease will be the parasites. That being said, there are certain things that can make the situation worse.

Very poor water conditions will make it more likely that these parasites can thrive. If you’re not doing a good job of maintaining your fish tank, then that’s going to make it much harder to keep your fish healthy.

Of course, improper water conditions will cause your clownfish to experience stress. When fish get stressed, they’re going to develop compromised immune systems.

Fish in this state will be significantly more vulnerable to getting infected. Brooklynella disease can wind up getting into your fish tank even if you’re doing things right, though.

Sometimes it enters your fish tank because you added a sick fish to the aquarium. You might have purchased a new fish recently, and it just so happened that this fish has Brooklynella disease.

Try to be very careful when you’re buying clownfish or other types of saltwater fish. You want to take the time to examine the fish to try to determine if it’s healthy or not.

Often, clownfish that are caught in the wild will be the ones that are infected with Brooklynella disease. It’s much rarer when you’re talking about captive-bred clownfish.

Not every pet store is going to specify whether the clownfish that they’re selling are caught in the wild or if they’re captive-bred fish. It’s going to be wise to try to do your research or ask questions to avoid putting the rest of your fish tank in danger.

This is why it’s crucial to buy healthy fish from a reputable source. Even then, it’s probably going to be safest to quarantine new fish before adding them to your community fish tank.

You can quarantine a fish in its own fish tank for a period of time to try to ensure that it isn’t sick. Be sure to properly acclimate the fish so that you don’t encounter problems with making the fish sick.

The best thing to do will be to quarantine the fish for at least two weeks. Some go so far as to quarantine fish for up to four weeks to be as safe as possible.

How Do You Treat it?

Lone Clownfish

Treating Brooklynella disease can be approached in a few different ways. Some people choose to isolate any fish that shows symptoms of the disease.

You could transfer sick fish to a hospital tank for special treatment. Since you had a sick fish in your tank, all of the fish in the original tank will be at risk of contracting Brooklynella disease as well.

The most common treatment that is used to combat this parasitic infection is known as formalin. Formalin contains formaldehyde gas and it can help you to get rid of parasitic infections in aquariums.

This is a powerful treatment that needs to be used with great care. If you use it without restraint, then you could wind up harming the fish.

You’ll be mixing the formalin with saltwater and then adding it to the tank as instructed. You should only be using the amount of formalin that you’re supposed to use based on the instructions that you have been given.

There are many other treatments that are commonly recommended to help with this condition. It’s fairly common for fish to receive some type of antibiotic or antibacterial medication.

Copper baths are another pretty common treatment that people turn to. It’s generally accepted that formalin treatments are the most helpful, but there might be other things that you can turn to if you aren’t able to use formalin for whatever reason.

If you need the best advice possible, then you could contact an exotic veterinarian who treats fish. An expert such as this will be able to walk you through the process so that you can be sure that things are being done the right way.

Some people also choose to give fish that are suffering from this disease a freshwater bath to provide them with relief. As you likely know, clownfish are saltwater fish, and freshwater will normally kill them.

In this situation, a brief freshwater bath might provide the fish with some relief. If you choose to do this, you’ll need to immediately place the fish in a hospital tank after finishing and keep it under hyposalinity conditions.

This should help to keep any free-swimming parasites from being able to infect your fish. Hopefully, the clownfish will get better as you continue to treat it and monitor it.

Will a Clownfish Survive This Disease?

It’s not easy to determine whether your clownfish will survive getting Brooklynella disease or not. The fish should indeed have a chance to survive if you catch things early enough.

Just understand that this is something that can kill clownfish pretty quickly. It doesn’t take too long for a clownfish to succumb to this infection if you aren’t taking steps to treat the fish.

In some cases, people won’t even notice that there is a problem until it’s too late. This is really worrisome since not everyone pays constant attention to their aquariums.

If you aren’t observing your fish each day, then you could miss the signs that something is wrong. Those who just go through the motions of feeding their fish might miss some important signs.

Catching the disease too late could mean that the fish won’t survive. However, it’s still worth trying to treat the fish to save it.

It might wind up surviving, and you’ll just have to see how things go. Also, not all of your fish are likely going to become infected at the same time.

There might be a situation where some fish will survive and others will not. Hopefully, you’ll be able to catch things early enough that all of your fish will be okay.

Final Thoughts

You’ve learned everything that you need to know about this terrible clownfish disease now. It’s a disease that can impact more than just clownfish, but it’s well known as something that wild clownfish have to deal with.

Captive-bred clownfish are less likely to carry Brooklynella disease. When you’re buying clownfish from a pet store, it’s going to be better to buy captive-bred fish.

Truthfully, captive-bred fish are better for many other reasons as well. They’re less aggressive than fish that were caught in the wild, and they should have an easier time adjusting to living in a fish tank.

If your fish starts to show signs of having Brooklynella disease, then you should take action right away. Treat the fish using formalin or some other type of recommended treatment.

Those who want to have the safest experience should seek the advice of an exotic veterinarian. A vet who treats fish will be able to give you the treatments that you need as well as specific instructions on how to do things.

Depending on the way that you want to go about things, it might be very beneficial to have professional help. You can also simply buy what you need and follow the instructions to avoid any issues.

Catching things early enough should allow you to save the fish. If you didn’t catch things early, then there’s a good chance that the fish won’t make it.

Now that you know the symptoms that you need to look out for, it’ll be easier to catch things before it’s too late. Pay attention to your fish so that you can take action when necessary.

Remember to quarantine new fish for two to four weeks before putting them in your community aquarium. Being careful should make it much easier to keep your fish healthy.

Let your friends and family know about this issue if they have clownfish. It could help them to avoid having significant problems and losing their fish to these parasites.

Share this post: