Red Clown Fish - Nha Trang, Vietnam

Clownfish were brought to public consciousness the world over by Disney. They aren't particularly friendly fish and, unsurprisingly, are particularly aggressive towards strangers. They display erratic intimidating behaviour when approached, darting around hyperactively trying to scare potential invaders, predators or divers.

Like many sea creatures, clownfish exhibit interesting sexual characteristics.  They are all born male and later mature into females.  The largest most aggressive female is found at the top of the dominance hierarchy.  Once transformed this change is irreversible.  If a female clownfish is removed from the group, one of the larger male clownfish will move up the pecking order and become female.

Clownfish live in a symbiotic mutualistic relationship with anemone.  The clownfish are protected in the sea anemone from potential predators while the anemone benefits from regular preening of parasites and nutrients from fecal matter.  Clownfish are also extremely beneficial as they feed on small invertebrates that may harm the anemone.

By performing an elaborate dance with a chosen anemone, rubbing against its tentacles, the clownfish slowly acclimate themselves with their host.  A mucus layer on the skin of the clownfish confers immunity to the anemone's lethal sting.