Moray eels, or Muraenidae, are a family of eels whose members are found worldwide. There are approximately 200 species in 15 genera which are almost exclusively marine, but several species are regularly seen in brackish water, and a few are found in fresh water.
Moray eel
Skull and pharyngeal jaws of a Gymnothorax miliaris (goldentail moray)
Gymnothorax undulatus occupying a dead patch reef, located in Kona, Hawaii
Echidna nebulosa occupying a live coral reef, located in Sabang, Philippines
Eels are ray-finned fish belonging to the order Anguilliformes, which consists of eight suborders, 20 families, 164 genera, and about 1000 species. Eels undergo considerable development from the early larval stage to the eventual adult stage and are usually predators.
Eel
The European conger is the heaviest of all eels.
Eel eggs hatch firstly into the leptocephalus larval stage.
Larval eels become glass eels as they transition from the ocean to fresh water.