FRESHWATER EELS - ANGUILLIDAE
General:
Usually catadromous fishes in tropical and temperate waters, except eastern Pacific and south Atlantic. catadromous  = move from freshwater to saltwater to breed (cf adradamous + move from saltwater to freshwater to breed e.g. some Salmonidae)

Eellike body with minute or embedded scales. Well developed pectorals but no pelvic fins; dorsal and caudal fin confluent with anal fin. All species are important food fishes and are sold fresh, smoked, or canned. Important aquaculture species based on captured juveniles (elvers); widely introduced. All spend their juvenile and adult life in freshwater, returning to the ocean to spawn and die. The leptocephalus larvae are marine with sharply pointed tail which distinguishes the family from the elopids. There is some doubt as to the validity of some of the fifteen species currently recognized.
Etymology
Latin, anguilla, ae = eel
AMERICAN EEL
Anguilla rostrata