8 Animals that Glow (Bioluminescent Animals)

Written by Jennifer Gaeng
Updated: May 14, 2023
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Experts believe that as much as 76 percent of marine life is bioluminescent. Land creatures like fireflies, mushrooms, and beetles are also out there. When an organism undergoes a chemical reaction, called bioluminescence, it produces light. Cold light has little or no heat, as opposed to warm light like that from a flame or the sun. There is a chemical reaction between the molecule luciferin and oxygen that causes light to be emitted and animals to glow.

Perhaps you’ve seen glowing corals or sharks; however, these animals are not bioluminescent. Unlike bioluminescence, which is a chemical process, fluorescence results from creatures reflecting back light that strikes them. It turns out that glowing is useful on occasion. A predator’s use of bioluminescent light can blind its victim or startle and stun it into submission.

Want to learn more and see pictures of this cool anomaly? Eight animals that glow are explained below. Let’s go!

1. The Pineapple Fish

Cleidopus gloriamaris is also known as the Pineapple fish. This means “splendor of the sea” from its Latin name. The armored fish can be found in harbors and reefs between 6 and 200 meters deep. Whenever a person closes their mouth, no one will ever know that they have bioluminescent organs in their lower jaw, which are located around the mouth’s corner. The pineapple fish is one of the eight animals that glow.

While the fish is young, the light is green, but as it matures, the hue changes to red. A whole decade is not out of the question for animals of this kind. It uses its luminous organs as a weapon to hunt for tiny shrimp. Like us, it communicates with flashes of light. Symbiotic bioluminescent bacteria called Vibrio fischeri are responsible for the light emission in the photophores.

2. Bobtail Squid

Hawaiian bobtail squid are tiny - only around 1 or 2 inches long

Hawaiian bobtail squid is too small to be dangerous.


The squid known as bobtail lives in harmony with a species of a bioluminescent bacterium called Vibrio fischeri. In exchange for giving food to the bacteria, the squid uses the bioluminescence for concealment; the ensuing blue-ish glow allows the squid to blend in with the nighttime waters. The U.S. military looked into the connection between their skills to conceal themselves and camouflage to see if they could learn anything useful.

3. American Pocket Shark

The American pocket shark (Mollisquama mississippiensis), which has only lately been found, uses an ingenious technique to catch its prey. Little glands under the shark’s pectoral fins secrete a bioluminescent fluid, luring food in for a closer look. It is one of the animals that glow.

4. Deep Sea Anglerfish

Deep Water Anglerfish, Blackwater Photo.

Deep Sea Anglerfish glow in the dark waters.

©Sam Robertshaw/Shutterstock.com

Most of an anglerfish’s existence occurs more than a thousand meters below the ocean’s surface, where it is completely black. Female anglerfish are distinguished from males by the presence of a bright lure on their foreheads. This lure looks like a rod with a light bulb at its end and is home to bioluminescent bacteria. Let your mind wander to the day you followed a warm, enticing light only to discover a mouth full of razor-sharp fangs waiting for you. Prey of the deep water anglerfish (remember Marlin and Dory in Finding Nemo?) meet this untimely end.

The bioluminescent lure of deep water anglerfishes attracts prey such as fish and crustaceans. Yet, the lures are only available to females. This is done both for mating purposes and to encourage males to approach females and fertilize their eggs.

5. Aequorea Victoria Jellyfish

Weakest Animals Jellyfish

Crystal jellies Aequorea Victoria, are a bioluminescent hydrozoan


, or hydromedusa, that is found off the west coast of North America.


This jellyfish is one of the animals that glow. The bioluminescent Aequorea Victoria is also known as the Crystal jellyfish. There are claims that this luminescent sea organism, discovered on the western coast of North America, is the most influential of its kind.

A flexible mouth and manubrium are present, as are up to a hundred radial canals that extend to the bell border. At the edge of the bell, you can see many tentacles. Nematocysts aid in the capture of prey and are housed in the tentacles. This substance lacks any discernible hue or transparency whatsoever. It is a poor swimmer and must come into physical contact with its prey in order to digest it.

6. Sea Sparkle

sea sparkle

Sea Sparkle is an incredible anomaly.

©iStock.com/casi ng

So, you think you’ve seen it all? Sea sparkling is a sight to behold, and its beauty cannot be fully described in words. There are many questions on whether sea sparkle is an animal or plant. However, we do know that it is a free-living, single-celled, bioluminescent dinoflagellate species (Noctiluca scintillans). They are known to be balloon-shaped cells with transparent cytoplasm. A cytoplasmic luciferin-luciferase reaction is responsible for the generation of light. Only after the water is stirred can humans notice the glow. The summer months see the greatest number of them. Being a heterotroph, sea sparkle relies on a varied diet that includes fish eggs, plankton, bacteria, and other dinoflagellates.

7. Bigfin Reef Squid

Bigfin reef squid

Bobtail squids are also known as glitter squid and are bioluminescent.

©Rhododendrites, CC BY-SA 4.0 <https://creativecommons.org/licenses/by-sa/4.0>, via Wikimedia Commons – License

Glitter squids, or Sepioteuthis Iessoniana, are a type of squid that belong to the genus Sepioteuthis. Its huge, elliptical fins run the length of the mantle’s edges. These fins give it an appearance similar to squid. Ranging from about 3.8 to 33 centimeters in length. Although lacking photophores, it is capable of producing visible light in the dark. This squid isn’t technically bioluminescent because it lacks the photophores necessary for the process. Its body changes color from red to green when exposed to light. Altering its skin tone and pattern is one of its skills and a reason why it is one of the animals that glow.

8. Bolitaeninae Octopuses

The subfamily Bolitaeninae consists of small pelagic octopus that can be found in nearly every ocean on Earth. There is a lack of consensus on the taxonomy. However, scientists now know there are two separate genera, Bolitaena and Japetella. These are tiny, transparent invertebrates with gelatinous bodies and laterally compressed eyes. The pygmy pelagic octopod Bolitaena pygmaea is very similar to Japetella in appearance. The ring-shaped photophore that mature females utilizes to woo males stand out among other physical characteristics. When the female octopus emits her yellow glow, it draws the interest of her potential partner. Deep water is where couples mate. This small octopus is one of the animals that glow.

The photo featured at the top of this post is © synthetick/Shutterstock.com

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About the Author

Jennifer Gaeng is a writer at A-Z-Animals focused on animals, lakes, and fishing. With over 15 years of collective experience in writing and researching, Jennifer has honed her skills in various niches, including nature, animals, family care, and self-care. Hailing from Missouri, Jennifer finds inspiration in spending quality time with her loved ones. Her creative spirit extends beyond her writing endeavors, as she finds joy in the art of drawing and immersing herself in the beauty of nature.

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