Chimaera, ratfish, or ghost shark, strange-looking marine fish belonging to the subclass Holocephali, class Chondrichthyes and thus related to sharks and rays. There are about 25 species (mostly in the family Chimaeridae), which occur in deep or cool waters of most seas. In Canada, 3 species in 3 genera (Hydrolagus, Harriotta and Rhinochimaera) occur in Atlantic waters and 1 species (Hydrolagus colliei) occurs in Pacific waters.
Chimaeras are elongate and scaleless and range from 0.5 to 2.0 m in length. The ventral mouth is overhung by a projecting snout which is sometimes lancelike. At the front of the dorsal fin is a strong spine with a poison gland at its base. The pectoral fins are large and winglike. Males have a clasperlike organ on the front of the head in addition to pelvic claspers. All species deposit eggs, each in an elongate, horny capsule.