The name spiny eel is used to describe members of two different families of fish: the freshwater Mastacembelidae

Mastacembelidae

The Mastacembelidae are a family of fishes, known as the spiny eels. The Mastacembelids are part of the Order Synbranchiformes, the swamp eels, which are part of the Actinopterygii ....

 of Asia and Africa, and the marine (and generally deep sea) Notacanthidae

Notacanthidae

The deep-sea spiny eels are a family, Notacanthidae, of fishes found worldwide below , and going as deep as .Their bodies of deep sea spiny eels are greatly elongated, though more tapered than in true eels. The caudal fin is small or nonexistent, while the anal fin is lengthy, as long as half of...

. Both are so-named because of their eel

Anguillidae

Anguillidae is a family of fishes that contains the freshwater eels. There are 19 species/subspecies in this family, all in genus Anguilla. They are catadromous, meaning they spend their lives in freshwater rivers, lakes, or estuaries and return to the ocean to spawn...

-like shape and sturdy fin spines.

Spiny eels originate from three places. The Middle East, Southeast Asia and Africa.

In Africa alone there are 43 species known from two genera: Aethiomastacembelus, with 19 known species, and Afromastacembelus, with 24 known species.

Spiny Eels from Sri Lanka, China, Southeast Asia and India are also from two genera: Macrognathus and Mastacembelus.

The most commonly found Spiny eels in the Aquarium trade are the Macrognathus and Mastacembelus from Sri Lanka, China, Southeast Asia and India. These include such eels as the Peacock and Striped Peacock, the Tire Track and or White spotted eel, the Zig Zag, Fire, Siamese, and Zebra eel's.