Bioluminescence

Bioluminescence is a special type of illumination created by most life forms in Subnautica. However, not all of them can generate light bright enough to actually help the player with night time navigation.

Trivia

 * The Stalker and Lava Lizard are the only two fauna having no true bioluminescent glands.
 * Bioluminescence is used by many real-life animals for counter-illumination, luring prey, attracting mates, confusing predators, mimicking other animals, communication, and as a warning to would-be predators.