Reptiles are wonderfully diverse in size, shape, color, and lifestyle. The reptiles, or Class Reptilia, include turtles, crocodilians, tuataras, lizards and snakes. Birds, dinosaurs, and numerous extinct groups may also be classified as reptiles.
Fish have scales and lay eggs.
But, unlike reptiles, all fish live in the water and breathe through gills. The scales of fish and reptiles look very different and are of different composition. Fish eggs are without a shell and are deposited in water. Fish are not reptiles. Amphibians have four legs, and often look like reptiles.