There are 30 species of anemonefishes belonging to the subfamily Amphiprioninae
within the family Pomacentridae
(damselfishes). The two clownfish, Amphiprion percula
(clown anemonefish or orange clownfish) and Amphiprion ocellaris
(western clown anemonefish of false clownfish) form a separate clade, alongside Premnas biaculeatus
, within the Amphiprioninae. The two species of clownfish are easily distinguished from other anemonefishes by their bright orange body colouration and three white bars. Amphiprion percula
and Amphiprion ocellaris
have similar body colouration, but separate geographical distributions in nature. Amphiprion percula
occurs in northern Australia, including the Great Barrier Reef (GBR), and in Papua New Guinea, Solomon Islands and Vanuata. Amphiprion ocellaris
occurs in the Indo-Malaysian region, from the Ryukyu Islands of Japan, throughout South-east Asia and south to north-western Australia (but not the GBR).
Like all anemonefishes, the orange clownfish has a mutualistic relationship with sea-anemones. Adults and juveniles live exclusively in association with a sea anemone where they gain shelter from predators and benefit from food captured by the anemone. In return, the sea-anemone benefits by gaining protection from predators and supplemental nutrition from the clownfish’s waste. The orange clownfish associates with two species of anemone, Stichodactyla gigantea
and Heteractis magnifgica
. Clownfish social groups typically consist of an adult breeding pair and a variable number of smaller, size-ranked juveniles that queue for breeding rights. The breeding female is larger than the male. If the female disappears, the male changes sex to female and the largest non-breeder matures into a breeding male. The breeding pair lay clutches of demersal eggs in close proximity to their host anemone. Eggs hatch after 7-8 days and the larvae disperse into the open ocean for a period of 11-12 days, at which time they return to the reef and settle to an anemone.
The orange clownfish Amphiprion percula
, which was immortalized in the film “Finding Nemo”, is the most recognised fish on Earth. It is also one of the most important species for studying the ecology and evolution of marine fishes. The orange clownfish is used to study patterns and processes of social organisation, sex change, mutualism, habitat selection and predator-prey interactions in marine fishes. It has been central to ground-breaking research into the scale of larval dispersal and population connectivity in marine fishes and how this influences the efficacy of marine protected area. The orange clownfish is also used to study the ecological effects of environmental disturbances in marine ecosystems, including climate change and ocean acidification. More than any other species, the orange clownfish has become a mainstay of research into the chemical, molecular, behavioural, population, conservation and climate-change ecology of marine fishes.