What were the earliest fish like?
The first fish have been jawless and finless. There is one such fish, the lamprey, that still exists. It appears like an eel, with a mouth like a sucker, sharp enamel and no fins. The hagfish is another early fish that can nonetheless be viewed today. It lives in saltwater and feeds off the insides of dead fish. It defends itself by secreting slime. Today, most different fish have jaws and fins.
