Is It Best to Keep Clownfish in Pairs?

More than 40 percent of marine and reef aquariums around the world are stocked with Amphiprioninae, a genus more commonly referred to as clownfish and that owes a significant portion of its popularity to the 2003 Pixar film Finding Nemo. Amphiprioninae are very diverse in terms of variants. The one featured on Finding Nemo is from the ocellaris family, which happens to be the most common among saltwater fish keepers. Since the orange clownfish is relatively small, you might be tempted to get a few for your tank, but this may not be a good idea. Unless the tank holds at least 200 gallons of water, the most ideal number of ocellaris sharing an enclosed ecosystem should always be two. The trusted aquatic experts from Aquatic Warehouse explain why.

Understanding Clownfish Behavior

Not all Amphiprioninae are schooling species, but ocellaris certainly are. Their schools can range between three and eight fish, but only one of them is a female. Only one male in the school will get to mate with the sole female. As can be imagined, there will be some fighting when this happens, but nothing too violent. The real aggression will ensue when the mating pair forms. Clownfish couples physically dominate the rest of the males into submission for reasons that will convince you to keep no more than two.

Clownfish Sex Changes

As a hermaphroditic species, ocellaris males are able to change their sex to female for the purpose of establishing a reverse harem they can dominate through aggression and territorial behavior. This happens in both natural habitats and aquariums. If you stock a tank with two male clowns, the larger one will likely transform into a female, but there will be no need to assert dominance because the couple won’t have schooling mates to push around. The female clown holds the upper position in a hierarchy of two, but the couple remains gregarious.

Anemone Symbiosis and Territorial Behavior

There’s an older idea that there should be at least one anemone in every tank stocked with clownfish. Back when these amazing fish were all wild-caught, the clownfish all needed anemone for refuge from predators. But in an aquarium there really shouldn’t be predators, and because 98 percent of all clownfish sold in stores these days are captive bred, the clownfish don’t even know what an anemone is. With that being said, many clownfish will in time take to an anemone, and it’s fun to watch the gyrations in the anemone with a pair. In coastal reef habitats, clown couples tend to stay on one side of the anemone while the submissive males stay on the other side. This keeps some of the aggression down. Clownfish pairs won’t fight over an anemone.

The Clownfish Couple Advantage

Aquarists with large tanks have been known to keep a school of five clownfish, and this seems to be a magic number aside from the aforementioned couple. The problem with three clowns is that the couple won’t leave the other male alone. In the case of four clowns, the male and female will split up and bully a respective male. The odd number of three other males will confuse the couple because they won’t know how to distribute the bullying, but this could be disrupted if you need to take out one male to place under quarantine. Thus, it’s better to keep only a pair of clownfish.

Whether you have a saltwater aquarium with clownfish or a tank with an array of freshwater fish, you’ll need several essential supplies to properly care for your aquarium’s inhabitants. At Aquatic Warehouse, we carry a wide array of aquarium monitors, filtration systems, heaters and coolers, and any other aquarium supply you need. Stop by our store in Kearny Mesa, order your supplies from our website, or give us a call with any questions you might have at 858-467-9297.