| Swamp eels | ||||||||||
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Macrotrema Monopterus Ophisternon Synbranchus |
The swamp eels (also written "swamp-eels") are a family (Synbranchidae) of freshwater eel-like fishes of the worldwide tropics. The family includes about 18 species in four genera.
These fish are almost entirely finless; the pectoral and pelvic fin are absent, the dorsal and anal fins are vestigial, reduced to rayless ridges, and the caudal fin ranges from small to absent, depending on species. Almost all of the species lack scaless. The eyes are small, and in some cave-dwelling species they are beneath the skin, and the fish is blind. The gill membranes are fused, and the gill opening is either a slit or pore underneath the throat. Swim bladder and ribs are also absent.
The marbled swamp eel Synbranchus marmoratus has been recorded at up to 150 cm in length, while the Bombay swampeel Monopterus indicus reaches no more than 8.5 cm.
Most of the species can breathe air. Many also burrow, and are found in the mud underneath a dried-up pond.