Clownfish are easily the most popular saltwater fish. They are usually the number one reason people get into saltwater aquariums. This is for good reason. They are hardy, stay small, are boldly patterned and brightly colored, and now effectively all of them are captive-bred (an unusual exception in the saltwater side of the hobby). And who hasn’t seen the movie we shall not name for fear of the mouse’s lawyers that made them even more popular?
One problem though is that clownfish are usually the first fish to go into a new saltwater aquarium. This isn’t ideal since clownfish are usually the most aggressive fish that will be in these tanks which means they really should go in last. Putting fish in from least aggressive to most aggressive is the best way to allow the less aggressive fish to settle in, start eating, and be truly comfortable before adding the more aggressive fish. This avoids the more aggressive fish from being outright aggressive with the new additions or simply intimidating less aggressive fish with just their presence even if they aren’t directly aggressive.
Gender
Clownfish can change gender. They start as immature males, then convert to mature male, then convert to female. In nature, a single anemone may be home to many clownfish, each with about a 20% size difference from one individual to the next. The largest is always female, the second largest is the mature male, and the rest are immature. If any individual dies, all the fish below that one simply move up one rung on the ladder. It usually takes them about one month to make the change. They cannot go back down though. So a small female in the presence of a larger female cannot go back to being male. This is why it’s important to be careful about creating a pair at home. If you have a female and you go to the store and find a great clown that is half the size of your female, if the one in the store has been alone for at least two months, it’s a female. If it was already a mature male and has been alone in the shop for a month, it’s now a female. If you take her home to your female, they will not get along at all even though they are so different in size and it won’t get better since she can’t change back.
I usually recommend sticking to just a single pair of clownfish. They are territorial and aggressive, so it’s too risky to try to keep multiple pairs together, even in a larger tank. If you want to keep a group together, I highly recommend you get them all at the same time from the same tank at the store so you know you don’t have multiple females or males. You may have to special order them, especially if you want multiple varieties to be part of your group, but it can be worth it.
Feeding
Feeding clownfish is easy. Since effectively all are captive-bred, they are all used to captive foods, usually pellets. It still doesn’t hurt to see them eat in the store since it’s still such a good sign that they are settled in and happy. For more information on feeding, please read the Feeding Saltwater Fish article.
Anemones
Some clowns just don’t take to anemones quickly. When I got my first pair in my most recent 75, I poured them in directly toward the anemone and they dove straight in. Other people aren’t so fortunate. Sometimes it just takes a little time, but some people have resorted to things such as playing YouTube videos of clownfish in anemones to show the clownfish what’s supposed to come naturally to them.
To make it even more complicated, many will host in all sorts of corals that are, or are not, very similar to anemones. Anything that vaguely resembles an anemone can become a surrogate. I’ve seen them happy to make a home in Xenia, Rhodactis mushrooms, Euphyllia, Trachyphyllia, finger leathers, and all sorts of other corals. This isn’t usually a problem at all unless it’s a small coral and the clown’s constant hosting causes the coral to not open (such as a small one or two-headed Euphyllia).
Bubble tip anemones are the best first anemone. They are hardy, colorful, easily available, and affordable. They are still anemones though, so it’s best to wait until the tank’s been running without any major issues for at least 4-6 months. It’s also ideal that the anemone is in, happy, and large enough to handle a clownfish before the clownfish go in. This sounds like a long time to wait to get clownfish, but it really does give you the best chance of success in the end and they should be the last fish anyway. Best of all, if the anemone is happy, you’ll soon have more since it will start splitting. This is just more free real estate to keep your clownfish happy.
Species Selection
I avoid all clownfish except ocellaris and percula, which look identical without an overly scientific analysis, especially now with all the color and pattern varieties. So just pick what you like and don’t be afraid to mix and match, they don’t mind.
Other species are just too aggressive for a typical community reef tank and will be too likely to cause problems even if they are added last. If you are absolutely in love with one of the other types of clownfish, give them their own tank so they can be happy without making other fish miserable, or keep them to more appropriate tanks such as predator tanks where they are large enough to not be eaten, they’ll hold their own.
Breeding and More Information
Clownfish can be bred in captivity, but it’s more advanced than can be properly covered in this article. If you are interested in breeding or just more of the nitty-gritty of clownfish, check out the book below, Clownfishes by Joyce Wilkerson.
Find it on Amazon