Fish are members of a group of ectothermic vertebrates, which possess gills and now lack limbs. instead, for moving underwater, they possess fins. They live in both salt and fresh water. Fish range from the tiny, primitive Haikouichthys to the huge Dunkleosteus. The word "icthy" means fish. fish survive today.
Fish, in general are the oldest type of vertebrates known to this day and the lobe-finned fish developed into another group of animals know as amphibians, who were the first vertebrates to live on land even if only partially. (For their own part, fish probably have evolved from the wormlike creatures similar both to the modern lamprey and the Cambrian Haikouitchthys.)
In Walking with... SeriesEdit
The following fish have appeared in Impossible Pictures works:
- sharks and rays: Devonian - Stethacanthus (Sea Monsters, Walking with Monsters); Jurassic - Hybodus (Walking with Dinosaurs, Sea Monsters); Cretaceous - an unidentified shark (Sea monsters); Eocene - Physogaleus (Walking with Beasts); Pliocene - Megalodon (Sea Monsters)
- ray-finned fish: Jurassic - Leptolepis (Walking with Dinosaurs), Leedsichthys (Sea Monsters); Cretaceous - Xiphactinus (Sea Monsters);Eocene - unidentified bony fish (Walking with Beasts) unidentified bony fish (Walking with Cavemen)
- lobe-finned fish: Devonian - Hyneria (Walking with monsters), Eusthenopteron ("The Complete Guide to Prehistoric Life" - mentioned); Triassic - unidentified lungfish (Walking with Dinosaurs); elsewhere - Coelacanth (books only)