Siamese Fighting Fish (alias Betta Fish) have evolved to survive in warm, murky South Asian ponds. Bettas have a special respiratory organ that allows them to breath air directly from the surface. In fact they inherently must do so. In experiments where the labyrinth organ was removed, the fish died from suffocation even though the water was saturated with oxygen. For this reason, Bettas must have access to the water surface to breath air directly from the atmosphere.
Desert Pupfish can exist in waters three times as salty as the ocean and water temperatures exceeding 95F. And without the snorkel gear.