Fish fins are specialized appendages that help fish swim and maintain balance in the water. There are several types of fins, including dorsal fins on the back, pectoral fins on the sides, pelvic fins on the belly, and caudal fins at the tail. Each fin serves a specific purpose, such as steering, stabilizing, or propelling the fish forward. Fins are made of a thin membrane supported by bony or cartilaginous structures called fin rays. The shape and size of fins can vary greatly among different species of fish, influencing their swimming style and habitat. For example, tuna have streamlined fins for fast swimming, while clownfish have more rounded fins for maneuverability in coral reefs.