The European eel (Anguilla anguilla) is a species of eel, a snake-like, catadromous fish. They can reach a length of 1.5 m (4 ft 11 in) in exceptional cases, but are normally around 60–80 cm (2.0–2.6 ft), and rarely reach more than 1 m (3 ft 3 in).
Freshwater/Saltwater Eels. Some 'true eels' in the Muraenidae family can be kept as freshwater eels due to the fact that they can occur in both freshwater and saltwater environments at different times of their lives, like the popular Snowflake Eel. But these fish are more commonly sold as saltwater eels.
Moray eel. Moray eels or Muraenidae are a cosmopolitan family of eels. The approximately 200 species in 15 genera are almost exclusively marine, but several species are regularly seen in brackish water, and a very few are found in fresh water.
Ophichthidae is a family of fish in the order Anguilliformes, commonly known as the Snake eels. The term "Ophichthidae" comes from Greek ophis ("serpent") and ichthys ("fish"). Snake eels are also burrowing eels, they are named for their physical appearance, they have long, cylindrical snakelike bodies.
An eel is any ray-finned fish belonging to the order Anguilliformes (/ æ ŋ ˌ ɡ w ɪ l ɪ ˈ f ɔːr m iː z /), which consists of four suborders, 20 families, 111 genera and about 800 species. Eels undergo considerable development from the early larval stage to the eventual adult stage, and most are predators.