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Why Are My Clownfish Fighting? (And What to Do About It)

Why Are My Clownfish Fighting? (And What to Do About It)

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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.

Keeping clownfish in your aquarium should be a very good experience overall. These fish are fun to watch and they’re generally not too difficult to care for.

Most of those who are new to caring for saltwater fish have a good time with clownfish. This doesn’t mean that everything always goes perfectly, though.

If two of your clownfish appear to be fighting each other, then you might be nervous. Is there something that you’ve done wrong that is making the fish want to fight?

Read on to learn about some of the reasons why clownfish might fight. This should help you to better understand the situation so that you can decide what to do.

Is it Normal for Clownfish to Fight?

Clownfish will sometimes fight each other and this really isn’t unusual at all. You’ll find that clownfish will choose to fight any other clownfish that tries to invade its territory.

For this reason, it usually isn’t a good idea to add a new clownfish to your tank at a later date. You typically want to buy two clownfish that have already formed a bond or you want to buy two young clownfish and put them in the tank at the same time.

This should make it more likely that the two clownfish will live in harmony with each other. When two clownfish have formed a bond they’ll mate with each other, and the two will be able to work out the pecking order on their own.

You see, every clownfish is born male and it can change its gender. This is something that can be done only once, but the larger and more aggressive fish is the one that becomes the female of the relationship.

So if you see one of the clownfish being aggressive toward the other, it could be that the two fish are simply establishing which one is going to be the female. Eventually, there should be a determination, and the male will wind up acting submissively toward the female.

When a male clownfish is being submissive toward the female, it’ll start twitching. Sometimes this twitching behavior will look odd, and many new clownfish owners get worried when they see it happening.

You might think that your clownfish is having a seizure or some type of medical episode. However, it’s just normal behavior where a male will show submission toward the larger, dominant female clownfish.

Keeping Fighting to a Minimum

Several Clownfish in a Tank

It’s certainly possible to keep fighting to a minimum in the fish tank by taking certain actions. There are many things that you can do to try to make the fish tank a more peaceful place.

The first thing to consider is whether you have a large enough tank. Your clownfish are more likely to get agitated and fight with each other if they’re living in a small aquarium.

It’s possible that the aquarium that you’re housing the clownfish in right now is too small. If the fish don’t feel that they have enough room, then they’ll want to fight over territory.

Sometimes clownfish will fight over food as well. When you’re feeding the fish, it’s important to spread the food evenly across the surface of the tank.

This should spread the clownfish out and keep them from fighting over one feeding area. If you don’t take precautions such as this, then you could spark a significant fight during feeding time.

You also need to consider the number of males in the tank. Generally, you don’t want to have more than two clownfish in the same fish tank.

There are exceptions to this rule to consider. For example, if you have an incredibly large fish tank, then there will be plenty of room for the fish to spread out and aggression issues wouldn’t be a problem.

However, in a normal home aquarium, having three or more clownfish in the same tank will be trouble. The dominant female will likely wind up fighting a lot with the new clownfish that you add to the tank, and the male won’t be any better.

You want to stick to the rule of just introducing two clownfish to the tank at the same time. Some enthusiasts have said that they’ve been able to raise three in one tank when introducing all three clownfish at the same time and while they were in the juvenile stage of development.

Take this information with a grain of salt, though. It doesn’t reflect the normal experience of aquarium enthusiasts.

If you want to take care of clownfish, then you should get a separate tank for any new clownfish pairs that you wish to purchase. It’s the safest route to take overall.

How Long Will Clownfish Fight?

Group of Clownfish

Now you’re likely wondering how long the clownfish will keep fighting. Is this something where the clownfish will continue to fight indefinitely or will they stop after a certain amount of time has passed?

Generally, the clownfish will only fight until one is able to establish dominance over the other. Sometimes this can take several months, but it might not take so long.

Once the female of the pair has been determined, the male should start showing its submission toward the female. There might be times where the larger female will “put the male in its place.”

This means being aggressive toward the male to get it to fall in line. You shouldn’t have to worry about this since things likely won’t go too far.

If you make the mistake of putting two females in the same tank, then they’re going to fight to the death in all likelihood. Unless you have a very large tank that would be impractical for most homes, it’s truly not wise to put multiple established females in the same fish tank.

Will Clownfish Kill Each Other?

It isn’t out of the question for clownfish to kill each other. As mentioned above, if you make the mistake of placing two established females in the same tank, then you’ll likely see one of the females get killed by the other.

The two will not be able to accept living in the same fish tank. They’ll just keep fighting until you either remove one from the tank or one of the female clownfish gets killed.

This is why you need to stick to the rule of only keeping two clownfish per fish tank. It isn’t too unusual for female clownfish to kill male clownfish either.

Sometimes things can get out of hand and a female will take things too far. The female is the larger fish of the two and might assert its dominance from time to time.

Depending on how things go, the smaller male clownfish could get killed. It’s unfortunate, but this has happened even when a pair has been mating for quite some time.

There’s also a good chance that you’ll never see this happen. It might depend on various factors that will be hard (or maybe even impossible) to determine.

All you can really do is ensure that you give the clownfish enough space. Don’t add too many clownfish to the same tank and continue to care for them properly.

Try to Prevent Stress

Cleaning a Fish Tank

Stress is something that might exacerbate clownfish aggression. Clownfish can sometimes be aggressive toward each other, but things will be worse if the clownfish aren’t receiving the proper care.

You want to ensure that the clownfish are living in good conditions to keep them healthy and happy. This means keeping an eye on the water parameters and keeping the fish tank clean.

Remember to change the water every week to keep the water clean. You should be changing out 15% of the water weekly to be safe.

If you get into the habit of cleaning the tank and changing the water weekly, then it won’t seem like an annoyance. The water parameters are something that you need to water constantly.

Always keep the temperature of the water between 74 degrees Fahrenheit and 79 degrees Fahrenheit. The pH balance of the water should be between 7.8 and 8.4 to keep things perfect for the fish.

It’s important to keep the pH balance from fluctuating too much as well. Try to test it often to see how things are going.

The ammonia, nitrate, and nitrite levels should always read 0 ppm. Ensure that the gravity of the water is between 1.021 and 1.026.

Final Thoughts

It’s true that clownfish will fight sometimes, and this might be scary as a fish tank owner. You don’t want your fish to fight because you’re worried that one might kill the other.

In most situations, the fighting will just be about establishing dominance. The clownfish pair need to determine which one is going to be the female in the relationship.

When this has been decided, the female might put the smaller male in its place from time to time. It shouldn’t kill the male when fighting with it, but there have been situations where this has happened.

You never want to put more than two clownfish in the same tank. It’ll simply lead to more issues with clownfish fighting, and your fish tank will never be a peaceful place.

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Tuesday 15th of March 2022

Question. Need advice. I have 2 clowns - one percula and one saddle back. They were bought at the same time. The saddle back was purchased larger and has always been the dominant fish. They have lived together peacefully for 4 years. This week they have started fighting. It’s gone on for three days. Both are more interested in the fight than in eating but are willing to eat. The saddle back has a sore on her mouth from trying to get to the percula. He was hiding behind rocks and she was scraping her mouth on the rocks trying to get to him. I’ve presently separated them. Can anything be done?


Thursday 17th of March 2022

Sorry to hear about your trouble. Has anything changed, like the water condition, type of food, etc. that could have led to increased stress levels? Separating them makes a lot of sense for now. You could also try to add more hiding spots for them, but it sounds like you already have some that aren't quite keeping them separate and happy. It's possible that one of them is sick and the other one is sensing it, which often leads to aggression.