All fishes are vertebrates and are equipped with gills for breathing. Over 25,000 species of fish have been identified, and we discover hundreds more each year. We can find fish in almost all waters of the planet, excluding only the harshest of water environments, such as the Dead Sea. Killifish living in the tropics of South America and Africa release their eggs, or spawn, as the dry season begins. Their eggs then lie dry in the ground for sometimes six months, until the next rain returns when their short life cycle begins again.
Amphibians are animals with moist, hairless skin which water passes through, both in and out.
Almost every amphibian lives the first part of its life in the water, emerging to live the remainder of life on dry land, but usually in or near water still. Amphibians were the first vertebrates to adapt to life on land. Amphibians live everywhere on Earth save Antarctica with the most widespread being frogs, which can be found almost everywhere except a few islands, and the driest of deserts. Salamanders inhabit the western hemisphere from North America to the northern part of South America. They're also found in Europe, the Mediterranean area, Asia, and Africa.