Dusky Damselfish

Juvenile analogues: New recruits of S. adustus are separated from S. diencaeus, S. leucostictus, and S. variabilis by having no stripes

Diagnosis: Damselfishes with 12 dorsal-fin spines and a mode of 15-16 soft rays indicate Stegastes and Microspathodon chrysurus. Although fin-ray counts broadly overlap among the other Stegastes with most species having 13-14 soft anal-fin rays and 18-20 pectoral-fin rays, S. adustus and M. chrysurus have a mode of 21 pectoral-fin rays. The two latter species have a slight divergence in anal-fin soft rays, with S. adustus having 13-15, while M. chrysurus have 12-13.

Juveniles are reddish orange above, with small bright blue spots on forehead and dark spots at upper pectoral fin base, dorsal fin, and caudal peduncle; colors disappear as fish grows larger (Ref. 26938). Adults dark gray to blackish with vertical black lines on body; a black spot, sometimes diffuse, at upper base of pectoral fins which are pale; other fins dark (Ref. 13442).

Oviparous, distinct pairing during breeding (Ref. 205). Eggs are demersal and adhere to the substrate (Ref. 205). Males guard and aerate the eggs (Ref. 205).

Dorsal spines (total): 12; Dorsal soft rays (total): 14 - 17; Analspines: 2; Analsoft rays: 13 - 15

Inhabits rocky shores exposed to wave action. Often in tide pools. Feeds primarily on algae and detritus. Territorial and pugnacious. Territorial herbivore (Ref. 57616). Generally common (Ref. 9710). Taken incidentally in traps and small-meshed beach nets (Ref. 5217).

Adults inhabit rocky shores exposed to wave action. Often in tide pools. Feed primarily on algae and detritus. Territorial and pugnacious. Generally common (Ref. 9710). Oviparous, distinct pairing during breeding (Ref. 205). Eggs are demersal and adhere to the substrate (Ref. 205). Males guard and aerate the eggs (Ref. 205). Taken incidentally in traps and small-meshed beach nets (Ref. 5217).

aquarium: commercial

Stegastes adustus, also known as the dusky damselfish or scarlet-backed demoiselle, is a species of damselfish in the family Pomacentridae. It is found at one- to three-meter depths on surging and wavy coral reefs in the Caribbean Sea, the tropical waters of the western Atlantic Ocean, and the Gulf of Mexico.