The fish are a diverse group of vertebrate animals that were the first ones to exist. They have fins for helping them swim, gills for taking in all the oxygen from the water, and as of later times, scales that serve as a good source of armor (although not as good as that of the arthropods). There are 3 types of fish: bony, cartilaginous, and jawless. In the beginning of time, fish were insignificant, and only served as prey for the arthropods. However, in the Devonian, they have risen up to become formidable predators, and the bony fish had split into two types of fish: ray-finned and lobe-finned. As time would pass, the lobe-finned fish would evolve into another group of animals: the amphibians.
Fish Throughout Time (note that those are not all the ones that exist)Edit