10% of fishes are successive hermaphrodites which means that they are male or female for a time and then they switch sex. Clownfish, its latin name Amphiprion is a case of successive hermaphrodism where sex determination is made by social factors.
Each family is organized auround an anemone with which they have a mutual relationship, and is composed by one dominant female, one reproductive male, and juveniles (immature et sub-adult males). There is no link between the size and age of individuals : small subadults are not necessarily young, the social structure of clownfish have an impact on the size of individuals. For cons, the female is always the oldest of group. The female has an aggressive behavior to juveniles ; there sperm production is inhibited by hormonal and behavioral factors : submission. When the female died the inhibition is lifted, the reproductive male becomes the female in 4 weeks (oestradiol rate increase) and one sub-adults become the reproductive male. This is a case of protandry : the species is firstly male and then female, to improve reproductive success.
When the reproductive time is come the male adopts a behavior signal jumping, fast swimming up and down to attract the female. It also becomes more aggressive towards his partner and shows off in front of her still or on the side, all fins deployed. The male chooses a nest site on a bare rock near the anemone. Sometimes he chews the tentacles of the anemone so they retract and thus frees up spawning in the disk of anémone. Anemones sandy bottoms do not offer surface conducive to spawning. The fish can solves this problem by bringing a suitable surface on its territory such as tests of echinoderms, bivalve shells, pieces of palm leaf or cans. This support nesting can thus be moved several meters until its anemone. Then the female swims slowly rubbing her abdomen on the rock, laying eggs, closely followed by the male fertilizes the eggs as and mesure. The nest can count from 600 to 1600 eggs.
Just before hatching, the embryo with its large shimmering pupils is visible through the transparent membrane. We also distinguish the red-orange yolk that gives the overall color of the eggs. Eggs hatch only at night, after 7 to 10 days. After hatching, the larvae spread in the plankton living in the ocean surface passively carried by currents. The larvae are transparent and are about 3-4 mm. The last larval period of 8 to 12 days and is one of the shortest among this fish family, which certainly explains the low range of species. The larval stage ends when the larvae reached the bottom. This initiates the metamorphosis into juvenile acquires its new colors. This transformation occurs in about one day. It is therefore vital for them to find a sea anemone to join, otherwise it will probably be eaten by a predator. Some species locate cnidarians following a chemical marker while others spot them on sight or by chance.
Clownfish are not directly threatened, but through the destruction of their habitat by global warming and human activities.