The Earliest fish appeared in the course of the Cambrian as little filter feeders; they continued to evolve throughout the Paleozoic, diversifying into quite a few kinds. The earliest fish with dedicated respiratory gills and paired fins, the ostracoderms, had major bony plates that served as protective exoskeletons from invertebrate https://maps.app.goo.gl/kTisAZCbSjAw6nkX8