The Scorpaenidae are a family of mostly marine fish (some live in brackish waters), widespread in tropical and temperate seas. They have a compressed body, and the head usually has ridges and spines. There are 1-2 spines on the operculum, and 3-5 on the preoperculum. Scales are normally ctenoid. Most Scorpaenidae have 1 dorsal fin, containing between 11-17 spines and 8-17 soft rays. Their anal fins typically have 1-3 spines, and 3-9 soft rays. Pelvic fins have 1 spine with 2-5 soft rays, whereas the large pectoral fin contains 11-25 soft rays. Not all species have a swim bladder, and most have venomous glands in the spines of their dorsal, anal, and pelvic fins.