Australian clownfish

Lore & Background

The side of A. rubrocinctus has blackish or dark brown sides with a red snout, breast, belly and fins. It has a single white head bar that is often poorly developed and lacks a pronounced black margin. Unlike some other anemonefish, it does not show color variations based on geographic location, sex, or host anemone. It is included in the tomato complex and shares similarities with other species in that group. A. frenatus is similar, but males are entirely bright red and the white head bar is more vivid on females. A. barberi was originally thought to be a geographic color variation of A. rubrocinctus but was described as a separate species in 2008; it lacks the dark brown or black sides and is geographically distinct. A. rubrocinctus is easily distinguished from the four other anemonefish species commonly found within its range: A. perideraion and A. sandaracinos have a distinctive white stripe along the dorsal ridge, while A. clarkii and A. ocellaris each have three white bars.

Reader's Guide

The Australian clownfish is significant as a specialized anemonefish with a small geographic range, being found only in the tropical seas of north west Australia from Ningaloo Reef to Groote Eylandt. Its relationship with host sea anemones is highly nested and specialized, hosted by only two out of the nine host anemones within its range: Entacmaea quadricolor and Stichodactyla gigantea. This specialization, combined with its small geographic range, elevates its risk of extinction, though its ability to use two different anemone hosts may reduce that risk. The species was not evaluated in the 2012 IUCN Red List, but the Northern Territory Department of Land Resource Management has listed it as least concern. Its protandrous hermaphroditism and strict size-based dominance hierarchy—where the female is largest, the breeding male second largest, and non-breeders progressively smaller—are key aspects of its social structure. The fish's natural diet includes zooplankton. Its legacy lies in being a distinct member of the tomato complex, with no color variations, and in the taxonomic clarification that separated A. barberi as a distinct species in 2008.

Did You Know?

• A. rubrocinctus is a sequential hermaphrodite with protandry: the breeding male changes to female if the sole breeding female dies.
• It is hosted by only two species of sea anemones: Entacmaea quadricolor and Stichodactyla gigantea.
• The species does not show any color variations based on geographic location, sex, or host anemone.