The common snook (Centropomus undecimalis) is a marine species in the family Centropomidae. The species is also known as the sergeant fish, linesiders, or robalo. The species is also known as soap fish.
The common snook is one of the largest snooks that can grow to an average length of about 50 cm. The species possesses drab coloration except for a distinctive black lateral line. It can also possess bright yellow pelvic and caudal fins, especially during spawning.
In regard to its feeding habits, common snook performs opportunistic predation as they will surprise attack their prey of small fish, shrimp, crabs and mollusks. In rare occasions, the species could be engaged in cannibalistic activities.