Bioluminescent fish are marine creatures that produce light through chemical reactions in their bodies. This ability helps them attract prey, communicate, and evade predators. Common examples include the anglerfish and lanternfish, which use their glow to survive in the dark depths of the ocean. The light produced by these fish comes from specialized cells called photocytes or from symbiotic bacteria. Bioluminescence can vary in color, often appearing blue or green, as these wavelengths travel best through water. This fascinating adaptation plays a crucial role in the complex ecosystems of the deep sea.