24 Janvier 2013
The Orangefin Anemonefish (Amphiprion chrysopterus) is probably the most famous fish in the world after the movie “Finding Nemo” was released in 2003. This small fish has become part of the underwater landscape in the Pacific Ocean. There is a large variety of clownfish. The most well-known is certainly the Ocellaris clownfish as portrayed as “Nemo” in the film.
The clownfish is a colorful fish with orange-yellow head and fins. Its flanks are brown. Colors may vary according to the species and their environment. With regards to the other species, « chrysopterus », it additionally presents two electric-blue lines on its sides. A young clownfish’s colors are clearer. It has 3 white lines including one that will disappear at maturity.
The Clownfish (sometimes known as,”anemonefish”) can measure 8 to 15 cm. It lives as deep as 40 meters in lagoons or oceanic slopes. It feeds on plankton and seaweed. The lifespan of the clownfish go up to 6-10 years.
A special feature of this species is the symbiotic relationship it has with some varieties of sea anemones. Indeed, the anemones - usually lethal for fish - seem to be inoffensive to the clownfish. The clownfish, therefore takes advantage of the anemone’s stinging venom to protect itself from predators using it as a natural defense habitat. One does not really know how this relation is possible and the benefits for the anemone. Although some theories just explain this connection through mutual protection.
During breeding season, the male clownfish builds a nesting site. After egg-laying and fertilization, it protects and tends to the nest. Eggs hatch in around 7 days depending largely to water temperature. Ten days later, the larvae are juvenile and have to find their own anemone habitat as soon as possible.
The clownfish lives in the anemone alone, in a couple or in a group. Each group is composed of an adult couple and other younger males. There is a hierarchical organization in the anemone: the sole unique female is at the top of the hierarchy. The oldest male is second. Each member can go up in the school hierarchy with the disappearance of those ranked above them. Because the clownfish is a hermaphrodite, the oldest male can easily replace the female in the hierarchy when it disappears. This group seems to be a well-constructed social structure.
In French Polynesia, the large communities of anemones in the coral gardens offer so many perfect sites for observing the clownfish. During your dives you will surely come encounter this colorful little fish in our tropical waters.
© photos : V.Truchet, Mathias