Fish: Form and Function SciREN Lesson Plan Carter Smith and Kathleen Onorevole

What can shape tell us about function?

Dorsal Fin Used for balance Sometimes contains sharp points for protection

Pectoral Fins Paired fins Used for locomotion and side to side movement

Pelvic fins Paired fins Stability while swimming Can be used like a kick-stand for fish that like to sit on the bottom

Anal Fins Paired fins Used for stability

Caudal Fin Used for locomotion The “engine” of the fish

What can a caudal fin tell us? If the fish is a fast swimmer If the fish is traveling long distances If maneuverability is important

Types of Caudal Fins

Round Caudal Fin Slow swimmers Usually live near reefs, because they are good a maneuvering around obstacles Majestic Angelfish

Forked Caudal Fin Fish that spend a lot of time swimming Not the fastest, but they are always in motion Usually live near shore, but not on reefs Channel Catfish

Square Caudal Fin Good maneuverability Bursts of speed Usually live near shore or on reefs Red Snapper

Lunate Caudal Fin Fast swimmers Swim for long distances (across entire ocean basins!) Dolphin Fish (aka Mahi Mahi)