How are fish adapted to life in water?

How are fish adapted to life in water?

the more evolved species of fishes have gills, which the fish constantly is passing fresh oxygenated water over- by opening and closing their mouths. they have developed different ways to sense their enviroments by feeling shockwaves in their lateral lines, or tasting with their tongues or barbels ( whiskers). they can regulate their body temperatures to adapt to extremely cold temperatures, some even have a form of 'antifreeze' in their bloodstreams.
some of the more rudimentary - rough fish can survive on very little oxygen, and can live in very warm low oxygen water.
there are even a few that can actually breathe air and walk from water hole to water hole.