Pacific Mutton Hamlet

Alphestes immaculatus has a strongly compressed, deep body with large eyes and a short snout and a straight forehead. The dorsal fin has 11 spines and 17-19 soft rays while the anal fin has 3 spines and 9 soft rays. It has a rounded preopercle with an obviously serrated rear edge and a large spine, which is usually covered with skin, projecting downward and forward at its angle. The head and body are marbled reddish brown in colour, with obscure bars and small dark and pale spots all over the head, body and dorsal, anal and caudal fins. The pectoral fins have 7 or 8 irregular horizontal series of small dark spots running across them. The maximum recorded total length is 30 centimetres (12 in) but they are more normally around 18 centimetres (7.1 in).

Alphestes immaculatusis found in the Eastern Pacific Ocean from southern Baja California and the Gulf of California south as far as Peru. It is also found around the Islas Marías and Revillagigedos of Mexico, the Galápagos, Malpelo Island in Colombia and Cocos Island in Costa Rica.