Nemo is a clown fish!
There are 27 known Clown fish species, but not all of them have been successfully kept in captivity. The Tomato Clown fish and the Percula Clown fish are two of the easiest and most frequently kept Clown fish species. In the wild, all Clown fish species will live among the tentacles of an anemone. Somehow, the Clown fish manages to avoid being injured by the dangerous anemone. Instead, the Clown fish will attract predators to the anemone, and before they manage to devour the Clown fish they will receive a fatal sting from the anemone. The anemone will feed on the predator fish and the Clown fish will eat the leftovers. Clown fish will also feed on dead anemone tentacles. We still do not know how Clown fish can avoid being paralyzed by the anemone, but some researchers have suggested that the fish might develop a slime that protects its entire body. This slime seem to be species dependent, because if you give your Clownfish a new type of anemone in the aquarium the fish will need some time to acclimatize itself to the new species. If you instead give you Clown fish a new anemone from a species that it is already accustomed to, your Clown fish will be instantly protected from the deadly sting.
Wild clownfish is found in warm waters in the Red Sea, Indian Ocean and Pacific Ocean. Clownfish are popular in marine aquariums since they are very beautiful and display vivid colours. Their coloration is typically yellow, orange or maroon and their body is usually decorated with distinct white stripes. The name Clownfish has probably been coined due to their vivid colouration and captivating behaviour. Many divers perceive the Clown fish as a funny jester, since it is much more active and less shy than many other fish species. The truth is however that the Clown fish is more interested in protecting its territory than entertaining divers. The Clown fish is a highly territorial fish and it will defend its anemone violently if necessary. You should not mix different Clown fish species in your aquarium unless it is very large and decorated in a way that creates natural borders. Mixing different Clown fish species in a small aquarium where they are not able to claim their own territories and stay out of each others sight will result in a lot of fighting. The Clown fish is a peaceful fish, as long as it doesn’t think that another tank mate is planning to steal his anemone or territory.
It is possible to breed many Clown fish species in captivity, even without an anemone. The anemone is needed to guard the Clown fish and its offspring from predators, and in the wild the Clown fish will always select an anemone as spawning site. In an aquarium without any predators the Clown fish can eventually feel safe enough to spawn even without an anemone, or use a fake anemone as spawning site. All Clown fish are born male. Clown fish live in small groups with a well established hierarchy. The largest male will be at the top of the hierarchy and eventually morph into a female. The second largest male will form a couple with her and they will breed. The rest of the males are simply hang-arounds. They can not fertilize the eggs, since their reproductive system is inactive. If the female is killed or otherwise removed from the group, the largest male will turn into a female and the largest of the non-breeding males will become a breeding male. If the male is killed or otherwise removed from the group, the second-largest male will simply take his place and his reproductive system will become activated.
