Evolution of fish

The evolution of fish began about 530 million years ago during the Cambrian explosion. One of the earliest jawless fish include Haikouichthys, a craniate. The conodonts were another Agnatha. The earliest jawed vertebrates developed during the late Ordovician period.

During the Devonian period, a great increase in fish variety occurred, especially among the ostracoderms and placoderms, and also among the lobe-finned fish and early sharks, which meant that this was the age of fishes.