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

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 (ray-finned fishes). In an evaluation of the family in 2004, the ...

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

Notacanthidae Notacanthidae, the deep-sea spiny eels, are a family of fishes found worldwide below , and as deep as . The earliest known spiny eel is '' Pronotacanthus sahelalmae'', from the Santonian of what is now Lebanon. Their bodies are greatly elongate ...

. Both are so-named because of their

eel Eels are ray-finned fish belonging to the order Anguilliformes (), which consists of eight suborders, 19 families, 111 genera, and about 800 species. Eels undergo considerable development from the early larval stage to the eventual adult stage ...

-like shape and sturdy fin spines. These two families are not related: the

Notacanthiformes The Notacanthiformes are an order of deep-sea ray-finned fishes, consisting of the families Halosauridae and Notacanthidae (spiny eels). The order is of relatively recent vintage; ''Fishes of the World'' (2006) lists it as the suborder Notacan ...

belong to the Superorder

Elopomorpha The superorder Elopomorpha contains a variety of types of fishes that range from typical silvery-colored species, such as the tarpons and ladyfishes of the Elopiformes and the bonefishes of the Albuliformes, to the long and slender, smooth-bodi ...

, whose members are characterized by having

leptocephalus Leptocephalus (meaning "slim head") is the flat and transparent larva of the eel, marine eels, and other members of the superorder Elopomorpha. This is one of the most diverse groups of teleosts, containing 801 species in 4 orders, 24 families, ...

larvae. The freshwater Mastacembelids do not share this characteristic and are popular specimens in the

aquarium trade Fishkeeping is a popular hobby, practiced by aquarists, concerned with keeping fish in a home aquarium or garden pond. There is also a piscicultural fishkeeping industry, serving as a branch of agriculture. Origins of fishkeeping Fish have ...

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

Sources

* http://www.fishinthe.net/html/section-viewarticle-54.html Mastacembelidae Notacanthidae {{Rayfinned-fish-stub