About Stegastes fuscus (Cuvier, 1830)
Adult dusky damselfish (Stegastes fuscus) have body color ranging from brownish-olive to dark grey, marked with fine, darker vertical stripes along their bodies. They have large fins, and the edges of the dorsal and anal fins sometimes have a blue rim. The dorsal fin contains 12 spines and 15 to 16 soft rays, while the anal fin contains 2 spines and 13 to 14 soft rays. This species can be told apart from the closely similar longfin damselfish (Stegastes diencaeus) by its shorter, less angular dorsal and anal fins. The maximum recorded total length of this species is 15 cm (5.9 in), and 10 cm (3.9 in) is a more common typical length. Juvenile dusky damselfish are pearly grey with blue spots on the top of the head. They have a large black eyespot rimmed with blue at the junction of the dorsal fin spines and soft rays, plus a smaller, identically colored eyespot on the caudal peduncle. Some juveniles found off the coast of southeastern Brazil have a vivid yellow and orange band running along their back and dorsal fin. Stegastes fuscus is known to occur in shallow waters off Brazil, where it is common on both rocky reefs and coral reefs down to depths of 40 m (130 ft). It has also been reported from the Caribbean Sea, but these records may actually be misidentifications of the separate species Pomacentrus dorsopunicans. An unconfirmed additional population has been reported from Senegal.
