The cusk-eel family, ophidiidae, is a group of marine bony fishes in the ophidiiformes order. the scientific name is from the greek ophis meaning "snake", and refers to their eel-like appearance. true eels, however, diverged from other ray-finned fish during the jurassic, while cusk-eels are part of the percomorpha clade, along with tuna, perch, seahorses, and others.

Source: Wikipedia