Synbranchiformes: Swamp Eels

This small order contains three families, enough to get its own webpage. They have eel-like bodies and lack pelvic fins. Almost all species live in freshwater.


Synbranchoidei: Swamp Eels

There is one family, Synbranchidae. They not only lack pelvic fins but pectoral fins as well, the dorsal and anal fins are vestigial, and the caudal fin is small to absent. The eyes are small, with some species having them below the skin. Most species can breathe air via suprabranchial pouches. They also lack gasbladders.


Unlike the previous suborder, the dorsal and anal fins are continuous with the caudal fins. They also have physoclistous gasbladders.

Chaudhuriidae: Earthworm Eels

This family completely lacks scales, lateral line, and the dorsal/caudal/anal fins are fused in some species. They get their name because they are the size and shape of earthworms.


By Haplochromis (Own work) [GFDL or CC BY-SA 3.0], via Wikimedia Commons

Mastacembelidae: Spiny Eels

These eels have isolated dorsal spines preceding the dorsal fin, giving this family its name.