CLASS CHONDRICHTHYES AND OSTEICHTHYES: FISH
juvenile emperor angel fish: Pomacanthus imperator
Fish are divided into two classes, Class Chondrichthyes and Class Osteichthyes. Chondrichthyes consists of all jawed, cartilaginous (have exoskeletons of cartilage) fish, such as sharks, while Osteichthyes...
consists of all bony fish, like salmon, trout, goldfish, lungfish, seahorses, eels- around 95% of fish are part of this class! All fish have a two- chambered heart, so oxygenated blood and blood without oxygen are mixed together. This means fish blood contains less oxygen than human blood, which is pumped through a four-chambered heart. For gas exchange, a fish uses gills. When a fish takes in water, the gills exchange carbon dioxide from the fish’s bloodstream for the oxygen in the water.
Would you believe me if I told you that the picture above was an angelfish? You probably think of angelfish as a fish with blue and yellow stripes, but emperor angelfish are actually born with blue and black stripes, then develop yellow and blue ones after a few years. This species can be found around the Indian or Pacific Ocean and are usually seen in reefs or lagoons in places with an abundance of coral. They feed mainly on sponges and tunicates.