Fish can produce mucus to protect their skin and reduce drag while swimming.

The tigerfish has sharp, interlocking teeth for catching prey.

Fish can have various types of scales, including cycloid, ctenoid, and placoid.

The goblin shark has a protrusible jaw that extends to catch prey.

Fish can exhibit schooling behavior to reduce the risk of predation.

The bowfin is a primitive fish with a lung-like gas bladder for breathing air.

Fish can have specialized adaptations, like the antifreeze proteins in Antarctic icefish.

The lanternfish has light-producing organs called photophores.

Fish have a closed circulatory system, with blood circulating through vessels.

The fish brain is divided into regions responsible for different functions, including movement and sensory processing.