Earth’s deep sea
Dragonfish: fangs, lights and ultra-black skin
Deep-sea dragonfish are small but fierce hunters of the dark: long, black, with fangs, rows of glowing dots along the body and, in many species, a glowing lure hanging from the chin. There are nearly 300 species, and some can do things no other fish can.
Quick facts
- Family: Stomiidae, the barbeled dragonfish, with nearly 300 species.
- Size: most are small, under about 30 cm; a few grow larger.
- Depth: mainly the twilight and midnight zones, a few hundred to a couple of thousand metres down.
- Where: oceans worldwide.
- Food: fish, shrimp and other animals, caught with long fangs.
Built to hunt in the dark
Dragonfish have big jaws full of long, sharp teeth, and many can open their mouths very wide to take large prey. Rows of light organs run along their bodies, and many species have a barbel, a long thread hanging from the chin, tipped with a glowing lure that draws prey close.
Ultra-black skin
A 2020 study found that some deep-sea fish, dragonfish among them, have skin so black it absorbs more than 99.5% of the light that hits it. Packed layers of pigment soak up light instead of bouncing it back. That matters when you hunt with a light on your chin: it keeps your own glow, and your prey’s, from showing you up.
Seeing red
Most deep-sea animals cannot see red light. The stoplight loosejaw, a dragonfish, makes red light from an organ under its eye and can see it, thanks to a pigment related to chlorophyll that probably comes from its food. It hunts with a beam nobody else can see. Its name comes from its jaw, which has no floor of skin, so it can snap shut fast.
Black dragonfish and their strange young
In black dragonfish, females grow several times bigger than males, and the young look nothing like the adults: their eyes stick out on long stalks, which shrink back as they grow.
Dragonfish vs anglerfish
Read more about anglerfish and the other deep-sea fish.
| Dragonfish | Anglerfish | |
|---|---|---|
| Lure | On a barbel hanging from the chin | On a fin spine on the head |
| Light | Their own light organs along the body | Glowing bacteria in the lure |
| Body | Long and slim | Round, with a huge head |
Dragons in Fish of Ganymede
The game’s Dragon body plan has the fangs, the chin barbel and the rows of lights, and lives in the deep zones of Ganymede’s ocean. Catch one free in your browser.
Questions
Are dragonfish dangerous?
Not to people. They are small and live far below where humans swim.
Why do dragonfish glow?
To lure prey with a glowing chin barbel, to signal to each other and, in some species, to light up prey with red light others can’t see.
More guides
The real deep-sea fish behind our alien fishThe strangest real deep-sea creatures: anglerfish, dragonfish, the gulper eel, barreleyes and hatchetfish. How they hunt, glow and survive in the dark.
The gulper eel: a deep-sea fish that is mostly mouthThe gulper eel, or pelican eel, is a deep-sea fish with a huge, loosely hinged mouth and a glowing tail. Where it lives, what it eats and how big it gets.
Hatchetfish: deep-sea mirrors and river fliersTwo very different hatchetfish: silver deep-sea fish that hide with belly lights, and freshwater hatchetfish that can leap out of the water. Facts and size.