The Ocellaris Clownfish (Amphiprion ocellaris) is one of the most popular and well-known saltwater aquarium fish and has especially gained popularity since the release of Disney's "Finding Nemo". This clownfish has the appearance that most people think of for a clownfish - a bright orange body with three white bands narrowly outlined in black. Ocellaris Clownfish are very similar to Percula Clownfish (A. percula). Percula Clownfish have wider black margins to the white bands as they mature; younger individuals are almost indistinguishable between the two species.
Clownfish are some of the hardiest and most traditional fish for marine aquariums. They generally come from two genuses - most are in the genus Amphiprion with one species in the genus Premnas - and all are found in the Pomacentridae family along with damsels and chromises. They are some of the mostly widely captive-bred fish, leading to more man-made variations becoming available like Misbars and Albinos as species are selectively bred and crossed.
It is usually best to keep one clownfish per tank, though a pair can sometimes be kept if one is significantly smaller than the other or are about the same size when added as juveniles. One fish will develop into a female and become larger in size while the other (or others, in large tanks) will remain male. As the fish mature, they may also become aggressive towards new arrivals (or hands in the tank), so be prepared for aggression to follow even if the new fish is large in size. Mixing captive-bred and wild-caught individuals is generally not recommended since their immunity and exposure to diseases and parasites may be different.
Clownfish are generally not fussy eaters, and will accept a range of frozen and prepared foods like flakes, pellets, and frozen formulas. They can benefit from some plant matter in their diet, although they are not considered herbivores and do need some meaty foods. Some clownfish can be sensitive to toxins, especially heavy metal based medications like copper.
Though the interaction between anemones and clownfish is amusing to watch, it is not necessary to the survival of either animal. Some clownfish will only host in specific anemones and vice versa. A host anemone should generally have a diameter of at least twice the length of the clownfish when introduced together for the best health of both the clownfish and the anemone. Captive-bred fish can also be less likely to use a host anemone than wild-caught fish.
Visit That Fish Blog for more information from our marine biologists on clownfish social structure and gender, anemone selection and preferences and other clownfish-related topics.