How Many Clownfish Can Live in a Tank?

Clownfish are very social animals and they love to interact with other clownfish and humans alike. When setting up a tank with different species of fish one of the first issues to solve is which fish can live together and how many of each fish you can have so that your tank is relatively harmonious.

Most tanks should only have a pair of clownfish, regardless of size.  Having more than a single pair can lead to one of them being bullied or killed, especially when dealing with more aggressive species like the maroon clownfish. Having a single clownfish in a tank can work but is not ideal.

It’s not quite that simple, however, and there are some situations where you can keep more than just a pair with no problem. Let’s take a look at those.

Clownfish | Photo 2227230 © Offscreen |

How Many Clownfish Can You Keep in a Tank?

Unfortunately, the number of clownfish you can keep in an aquarium isn’t as simple as knowing “how many clownfish per gallon” or anything of that nature.

With clownfish, they can become aggressive, especially during mating season, so it’s best to keep just one pair unless you know what you’re doing.

If you must try it, ocellaris and percula clownfish are probably two of the safest species to try it with, as they are a bit more laid back when it comes to other clownfish being in their tank. I would still recommend having another tank that you can move a pair over to if it doesn’t work out, however.

Also, I would make sure you only keep pairs and you don’t have an odd clownfish out. (Unless you’re keeping a tank with only 1 single clownfish in it.)

If you want to keep more clownfish, you can try what’s known as a harem tank, which I’ll discuss further down in the article. First, let’s take a look at what tank size you should have.

Clownfish | Photo 24742020 © Krzysztof Odziomek |

What is the Best Clownfish Tank Size?

A clownfish is not like any other fish. They are very social and live with their “clownfish family”.

Clownfish usually live in pairs or groups, especially during mating season.

Clownfish tanks need to be set up to create an interesting environment that will allow them to feel safe and keep themselves entertained.

For most Clownfish an ideal tank size would be at least 20 gallons. This provides enough room for the fish to swim and keep entertained without being too big or too small.

This isn’t true for all species of clownfish, however. Here is a list with the minimum tank size for various types of clownfish.

  • Maroon Clownfish – 30 gallons
  • Saddleback Clownfish – 40 gallons
  • Allard’s Clownfish – 50 gallons
  • Oman Clownfish – 30 gallons, 55 for a pair
  • Tomato Clownfish – 30 gallons

If you’re setting up a harem tank, you’ll want a bigger tank than is listed above, so you should decide how many clownfish you want to keep and then size your tank based off of that. Ask around on one of the forums for the proper size for the harem setup you want to have, and you should get a solid answer.

Can you Keep Clownfish in a Harem Tank?

Can you keep clownfish in a harem tank? Yes, but it is not recommended for beginners.

In nature, Clownfish do live in groups of more than 3 fish and usually, there is one dominant fish and several males who are smaller and more passive. This arrangement, for whatever reason, is more difficult to make work in aquariums, so the setting up of a harem tank containing a group of Clownfish is not simple.

Clownfish | Photo 18447318 © Marjan Schmit Visser |

Naturally, there is a hierarchy in the Clownfish world. At the top is the dominant female and then there are two distinct kinds of males. One type of these always remains as males and are less aggressive. Another type of male is more dominant and perhaps slightly larger and has the tendency to transform into a female if required. This second kind of male is a competition of the dominant female and needs to be kept in its place by her so that it does not pose a threat as another dominant mating partner of the males she has in her harem.

Those who wish to set up a harem tank try to mimic this natural phenomenon, but as you would think, it can be difficult to get the fish to adapt to the tank and get along peacefully. In reality, fish may fight and some fish may die in this process.

However, more experienced fish owners set up successful harem tanks all the time. Let’s walk through some tips for keeping a harem tank of your own.

Ocellaris Clownfish | Photo 141139758 © Vojcekolevski |

If you want to learn how to set up a Harem Tank filled with Clownfish, there is an excellent series of videos by BRS you should watch, starting with this one.

If you’re going to keep a harem tank, percula or ocellaris clownfish are what you should start with. They are going to be less aggressive, so it’s more likely to work out for you.

Here are some basic steps to making a harem tank work. (You’ll want to do a lot more research before trying it yourself. This is just a few tips to improve the process.)

  1. In order to create a successful harem tank, introduce a number of sexually immature clownfish to your aquarium. Clownfish tend to pair up and as they can change sex, the more dominant fish in any pair can become a female. Eventually you’ll get a dominant pair.
  2. You’ll also want to make sure that all of the clowns you’re keeping are from the same clutch, as this will lead to fewer issues down the road. Most, if not all, of the successful harem tanks that have been kept have been with clowns from the same clutch.
  3. If you don’t have them from the same clutch, they should all at least be juvenile, possibly as young as you can get them.
  4. Feeding your harem heavily is another key to making a harem tank work.
  5. Expect fighting while the clowns figure out their hierarchy and who is the dominant male and female. Some clowns may die during this process.

It’s important to note that even after some success, the clowns in your harem can still get aggressive. BRS ended up separating the harem (made in the video I linked above) into pairs in different tanks due to aggression issues that cropped up after months of successfully keeping the harem.

This is something you also should be prepared for.


For most saltwater aquariums, you should only keep a solo clownfish or a mated pair of clownfish in a tank.

If you’re more advanced and are up for a challenge, keeping a harem tank will allow you to keep many more clownfish, but you should have places to separate them out into if the harem doesn’t work out.

Good luck with your clownfish!