Food is often limited and patchy in the mesopelagic, leading to dietary adaptations. Common adaptations fish may have include sensitive eyes and huge jaws for enhanced and opportunistic feeding. Fish are also generally small to reduce the energy requirement for growth and muscle formation. Other feeding adaptations include jaws that can unhinge, elastic throats, and massive, long teeth. Some predators develop bioluminescent lures, like the tasselled anglerfish, which can attract prey, while others respond to pressure or chemical cues instead of relying on vision.
