Bicolor Damselfish
Stegastes partitus
    Ecological Descriptors
Habitat Size (cm) Diet Behaviour Sex 
Co/ R 10 Pla, Veg Ter F
Adult: Body relatively elongate, robust, compressed.  Dorsal and anal fins short, not reaching base of tail fin, having soft lobes with angular tips. Tail bluntly forked, lobes with angular tips. 
Front half of body usually black, with yellow margin..
Adult colouration in the Tropical Western Atlantic region is highly variable and with intergrading patterns. In Antigua, the form is usually of a white head and body, with varying degrees of a yellow band seperating the two, plus a yellow pectoral fin and white tail. On other islands, morphs may include almost soley black/ grey, or almost wholely white.

Juveniles:  Like adult (unlike many other Stegastes congenerics).

Inhabits shallow coral reefs and isolated patch reefs in deeper water up to 25m. Algal feeders, which unlike other Stegates also feed on plankton (as per Chromis spp) This species is aggressively territorial around a small area, however may form groups with up to 20
other individuals. In this case there will be a dominant male at the head of the group. Should the alpha damselfish be challenged by a younger male and lose, the alpha position is passed onto the winner therefore dominance is dependent on the ability of the damselfish.

Life Cycle:
Adults spawn demersally following a unimodal lunar cycle with year-round reproduction and seasonal reproductive peaks from April to November. Produce a "3 pulse chirp" sound during courtship. Males provide parental care to the eggs; however, after hatching (~3.5 days), larvae enter the pelagic environment and the pelagic larval duration ranges between 24 and 40 days. After settlement, the adults are sedentary, defending small feeding territories indefinitely. The thirty days of larval development allows for the potential for long-distance dispersal. 
Bicolor Damselfish
Bicolor Damselfish
(C) Dr P Ryan/ RyanPhotographic