Why do some fish have bioluminescence?

Some fish have bioluminescence, meaning they can produce and emit light, as a form of communication, camouflage, and hunting. In the deep ocean, where sunlight doesn’t penetrate, bioluminescent fish use light to attract mates, lure prey, or signal to other fish. For example, the anglerfish uses a glowing lure to attract smaller fish within reach. The light is produced by chemical reactions in special cells called photocytes. This adaptation helps fish thrive in dark and deep-sea environments.