Animals That Glow in the Dark
Bioluminescent animals that produce their own light — fireflies, deep-sea fish, glowing plankton, and more — plus fluorescence vs bioluminescence.
Global Animal Guide · July 10, 2026
Quick answer
Animals that truly glow make light with chemistry (bioluminescence): fireflies, railroad worms, many deep-sea fishes and squids, some jellyfish and comb jellies, and bioluminescent plankton. Other species only fluoresce under UV — they re-emit light, they do not produce it. See our bioluminescence explainer for the chemistry.
Last updated: July 2026.
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Frequently asked questions
Do sharks glow?
Some deep-sea sharks are bioluminescent; many 'glowing shark' photos online show fluorescence under artificial light.
Why does the ocean glow at night?
Often dinoflagellate plankton disturbed by waves or boats — a bioluminescent display.