Bioluminescance is an adaptation in deep-sea animals, that is, they can generate their own light with the help of some internal condition. For example, the Anglerfish, a deep-sea dwelling fish. It is not only limited to aquatic animals, the firefly, an insect, alo showing traits of bioluminescance.
Bioluminescence is the emission of light by a living organism, such as a firefly.