Eyelight Fish Photoblepharon palpebratum
The most characteristic feature of this small fish is the large light organ under each eye. The blue-green light can be turned on and off using a black membrane like an eyelid. Eyelight fish are active at night, often feeding in large groups, and use the light to signal to other individuals, startle predators, and find small planktonic animals to feed on. Eyelight fish are sometimes seen at night by divers on steep reef faces. Daytime sightings are rare, as eyelight fish usually hide in caves during the day.