Answer:
Eels are just elongated fish. Their ancestors looked like tarpon fish. Their fins were a disadvantage in tight spaces, streamlined creatures literally filled a niche. They are more related to the salmon than the pythons.
There is fossil evidence to suggest that pythons and all the other snakes may have evolved from burrowing lizards, such as the varanids. Which are more related to the geckos than to fish.
Explanation:
The confusion can be made because eeil genus name-Anguilla, comes from anguis, which on Latin means serpent.