The different stages or phases in the life history
of fishes markedly vary from the adult and the degrees of
difference vary in different groups. However, there is
no sudden metamorphosis in fishes and the change of form
is slow. The differences between the larvae and adults
of some fishes have led erroneously to the descriptions
of the early stages of eel as Leptocephalus, Molidae as
Molacanthus and Centaurus. Chaetodontidae as Tholichthys,
Schindleria as Heiinirhamphus and Lampreys as Ammocoetus,
Later, these generic names were given the status of stages
in the early life history of the fish concerned
