Maroon Clownfish

Phylum: Chordata

Class: Actinopterygii

Family: Pomacentridae

Genus: Premnas

Species: P. biaculeatus

***Premnas biaculeatus***, commonly known as **spine-cheeked anemonefish** or the **maroon clownfish**, is a species of anemonefish found in the Indo-Pacific from western Indonesia to Taiwan and the Great Barrier Reef.

## Description

The characteristic that defines this genus is the spine on the cheek. The colors of the body and bars vary according to sex and geographic location. Despite the common name maroon clownfish, only some females have a maroon body color, with a range of color to dark brown. Juveniles and males are bright red-orange. The fish has three body bars which may be white, grey, or yellow. Where the female bars are grey, they can be "switched" rapidly to white if fish is provoked. The size-based dominance hierarchy means in any group of anemonefish, the female is always larger than the male. A significant difference in size is seen in this species, with females being one of the largest anemonefish, growing up to 17 cm (6.7 in) while males are much smaller, usually being 6–7 cm (2.4–2.8 in).

### Color variations

The significant color variations for fish in this species are related to sex and geographic location. Male and juvenile fish are bright red-orange which darkens on the fish changing to female, ranging from maroon to dark brown. The body bars of the female are narrower and the body bars reportedly all but disappear in older females. At least three geographic variations in the color of females are found, with fish from East Timor to Australia retaining white body bars. In the central Malay Archipelago, the head bar tends towards a dull yellow, with the other two body bars being grey. In Sumatra and Andaman Islands, all three body bars are yellow for both male and female, and the female body color can range from a dull maroon to a dark brown. While other species have a blue tinge to their body bars, *Amphiprion chrysopterus* and *A. latezonatus*, this geographic variety, is the only anemonefish to have yellow or gold body bars.

**Central Malay Archipelago**

The female in the Central Malay Archipelago, from North Sulawesi and the Philippines in the north to Komodo Island in the south, has a dull-yellow head bar and grey body bars. Male and juvenile fish are bright red-orange with white bars.

Female from Gilli Lawa Laut, near Komodo Island showing the gold tinged head bar and distinctive cheek spineMale at Bunaken island, North Sulawesi, showing the bright red-orange colors and three white body barsFemale at Bunaken island, North Sulawesi, showing the dull-yellow head bar and grey body barsThe male is significantly smaller than the female, with the female showing the dull-yellow headband, from the Apo Island the Philippines.
## Distribution and habitat

*P. biaculeatus* is found in the Malay Archipelago and Western Pacific Ocean north of the Great Barrier Reef.

### Host anemones

The relationship between anemonefish and their host sea anemones is not random and instead is highly nested in structure. *P. biaculeatus* is highly specialised with only one species anemone host, *Entacmaea quadricolor* bubble-tip anemone, predominantly with the solitary form. The fish chooses the host and one of the primary drivers for host selection is thought to be competition.  *E. quadricolor* is highly generalist, hosting at least 14 species, around half of all species of anemonefish. With such competition, *P. biaculeatus* is considered to be the most territorial of all anemonefish. Competition alone, though, does not explain the preference of *P. biaculeatus* for the solitary form of *E. quadricolor*.

## Trivia

* The prototype of this species looked more like A. Percula