Tuesday, July 10, 2007

False Percula/Clownfish - Amphiprion ocellaris

The Ocellaris Clownfish, also known as the False Percula Clownfish, False Clown Anemonefish, Common Clownfish or "Nemo" from the great Disney adventure movie "Finding Nemo" is found associating with anemones throughout the Indo-Pacific. It can attain a length of 3.2" (8 cm) in the wild, but aquarium specimens rarely exceed 2" (5 cm) unless they are imported large. The color pattern is the most important feature used to identify anemonefish. Normally this clownfish has bright orange with three white bars, the middle one with a forward-projecting bulge and its bars have narrow black margin.

Clownfish has no external characteristics to differentiate male and female, all clownfish are sexually immature when hatched. Meaning that the fry do not have a pre-determined sex, they are born male with active male and dormant female reproductive organs and develop into males and females depending on the hierarchy of the school. If the female dies, then the dominant male will sex-change into a female, and a non-dominant male will change into a dominant male. This allows anemonefish inhabiting one anemone to remain self-sufficient in that if the female dies there is no need for the male to find a new mate. The responsibility for caring of the eggs becomes the "new" female's job! A pair will lay eggs along the base of the host anemone, using it to protect the eggs. The eggs normally appear orange in color. They care for their spawn by fanning the eggs with their fins, removing litter or dead eggs using their mouths with great precision, and keeping other fish away.

Anemonefish have a special symbiotic (mutaully beneficial) relationship with sea anemones. Normally, the nematocysts (stinging cells) of an anemone's tentacles discharge when fish brush against the tentacles, paralyzing the fish. But anemonefish appear to be at home among the tentacles, even hiding among them as predators approach. There are many theories concerning the mechanism that makes this possible, but the most widely held view is that these fish have a special biochemical makeup of their mucus layer that provides protection from the stinging cells.