Clownfish seem like adorable little creatures after a Disney movie that depicted them as such, but if you have ever owned clownfish, you may know the dark truth about these cuddly guys and gals, especially if you have ever had a maroon clownfish.
I’ve had people practically in a panic when they ask me if clownfish are cannibals.
Clownfish are cannibals because they will eat their babies after the eggs hatch. Adult clownfish will also eat young clownfish if they are small enough to fit in their mouth. Adult clownfish will sometimes eat another adult clownfish after letting their aggression go too far.
I know this is not the pretty picture from ‘Finding Nemo’, but sometimes the truth hurts so let’s explore this in more detail to better understand it.
Will a Clownfish Eat Other Clownfish?
Clownfish Cannibals Eating Adult Clownfish
Clownfish are so aggressive that there are many reports from owners of clownfish attacking each other but we are here because of the rare case when an adult clownfish eats another adult clownfish.
It usually happens because a clownfish has been in the tank by itself for a while when another clownfish is introduced to the tank.
When clownfish are born they are all males. Usually, the bigger clownfish in the group becomes dominant and changes into the female as the female is always dominant when it comes to clownfish.
If you just dump a new clownfish in your tank, one of them may be a female or both. If they are both females, they will probably fight to the death which makes them cannibals.
I have read reports of one of the clownfish attacking the other so viciously that it tore it apart and ate it piece by piece.
Sometimes the account of the attack is so terrible that other experienced fishkeepers don’t believe it.
Some clownfish such as maroon clownfish are so mean that you have to be careful if you put them in pairs regardless because the dominant one may eat the other.
Divers have even reported maroon clownfish attacking them when they were underwater, even biting at their diving goggles repeatedly.
Clownfish Cannibals Eating Young Clownfish
Clownfish are omnivores which means they eat both plants and meat so they are not above eating young clownfish if it will fit in their mouth.
This is also rare but happens more often than an adult clownfish eating another clownfish.
This usually stems from aggression but sometimes clownfish will eat a smaller one because they are hungry.
There seems to be a consensus online that clownfish grow to about 4.3 inches on average with some types getting as big as 6 inches so they could certainly fit a young clownfish in their mouth.
As stated above though, sometimes they will tear it apart and eat it in pieces.
They may not seem like such powerful creatures but many a clownfish owner has found out the hard way when they put their hand in the clownfish tank to do maintenance just to feel the sharp pain of a clownfish biting their hand.
Clownfish are so mean that they will even attack the soft part of the skin in between your fingers.
Clownfish Cannibals Eating Their Babies
Clownfish males protect and watch over the eggs until they are hatched, while the female is more of a watchman for the surrounding area.
The male clownfish will already start eating the eggs but only if there is something wrong with one of the eggs, so the bad egg doesn’t spread to the rest of the batch.
However, when the eggs are hatched, the babies are on their own and the clownfish will eat them.
If clownfish will eat their eggs then that makes them cannibals.
Why are Clownfish Cannibals
It is the innate nature of the clownfish to be aggressive. You could say it is by design because they were meant to live in the coral reefs of the wild sea.
There are predators everywhere in the ocean and clownfish are just a snack to many of these predators.
The clownfish can fight some predators off which is why they are so aggressive, even toward their aquarium caretakers.
Clownfish are also omnivores which means they will eat both meat and plants. Their appetite is renowned for accepting a wide variety of foods.
Plus, clownfish don’t think they are doing anything wrong by eating other clownfish. If they did, they wouldn’t eat their babies, much less other adults.
If a clownfish accidentally kills another clownfish during a fight, they figure they might as well not let the food go to waste.
How to Keep Your Clownfish From Becoming Cannibals
Make Sure You Buy Captive-Bred Clownfish
When clownfish are in the wild they are usually found living with an anemone in some coral like in the Nemo movie.
The coral can be a wild place and clownfish are very territorial so they are used to being aggressive and protecting their territory.
If you then place them in an aquarium, they will bring their territorial instincts with them and may go too far with their aggression killing another clownfish.
In the wild, they are constantly in danger of being eaten by anything bigger than them so they may constantly fight with tankmates in an aquarium.
Buy Paired Clownfish
If you want a pair of clownfish that are used to each other so you don’t have to worry about aggression or fighting then buy a pair that are already living together.
You can usually find clownfish together at the pet store, so ask about them and even observe them to make sure they are getting along.
If you don’t keep your clownfish full of food they are going to start looking at one of their tankmates as a juicy meal.
You can put a plastic, glass, or acrylic divider in the middle of your tank if your two clownfish can’t get along.
If you don’t want a divider, and if your tank is big enough, you can put two different territories on each side of the tank with some empty space in between and hopefully, the aggressor will stay in one of the territories and vice versa.
You can even take the aggressor back to the pet store and try a different tankmate.
You need to keep your tank clean so your clownfish don’t get stressed out as this can make them temperamental.
If their water is clean and they are well-fed, they are less likely to lose their temper and attack their tank mate.
Try to Keep Two Clownfish
It is best to keep two clownfish, especially ones that were already living together when you bought them.
Clownfish are all born male and then the bigger clownfish turns into a female and dominates the others.
She will choose the second most aggressive fish as her partner and they will bully and dominate any other clownfish, so it is easier to just keep a pair of clownfish in your tank.
If you put two males together, one of them will most likely turn into a female.
The point is they may go too far with their aggression and end up eating one of the odd ones out.
Have an Anemone in the Tank
Clownfish are known for living with an anemone in the wild so if you put one in their tank, it will reduce their aggression.
Although they will still have some because the anemone is their territory, especially if you have too many clownfish together.
Make Sure There is Enough Space and Hiding Places
If you have two clownfish in your tank and one is the aggressor, it always helps to have more space and hiding spaces for both clownfish.
The aggressor may end up being satisfied with her/his area while leaving some space for the bullied clownfish.
This will also give the bullied clownfish more chances to hide or escape.
Adding a Second Clownfish the Right Way
Make sure the clownfish are of the same species and it is best to add a second clownfish that is a juvenile that is still male so they won’t already be stubborn in their ways.
One of them will probably eventually become a female and the dominating one of the group.
I hope we have shown you that clownfish are predators, why, and how to prevent it. If you liked our clownfish article, please check out our other ones.