Drifting aimlessly in the deepest parts of the tropics, the Coral Glowshark is so old and slow it has an ecosystem of coral reefs growing all around it. The Glowshark eats some of the coral near its nose every few years to sustain itself. Together they form a self-sustaining relationship with the coral so that the coral has access to more food by being mobile, and in return, they provide an effortless source of food for the shark. With their heartbeat stretching as far as one beat per 12 hours, no one truly knows how old they are.