Anglerfish: The deep-sea fish with a lantern on its head

The anglerfish lives in the deep sea, where sunlight never reaches and the water is black and cold. It has a special piece of equipment — a glowing "little lantern" hanging above its head. In the dark deep, that light is its cleverest hunting tool. Let's meet it.

Its body

The anglerfish measures from about 20 centimetres to 1 metre depending on the species. Its most striking feature is a rod-like growth on its head, tipped with a glowing "lantern". Remarkably, the light is not made by the fish itself: it is produced by a colony of glowing bacteria living in the lantern — the fish provides shelter and nutrients, the bacteria produce the light. A partnership.

Its mouth is large, lined with long, backward-pointing teeth. Once prey is bitten, it is like sliding into a pocket that lets you in but not out.

Its life and reproduction

The anglerfish is a carnivore, using its "lure lamp" to draw small fish and crustaceans close before swallowing them. In the food-scarce deep sea, finding a partner is very hard. So in some species the tiny male bites onto the female's body and stays with her for life — one of the ocean's strangest families.

A note for grown-ups

You could play a "find things with the lights off" game with a child, then talk about how dark the deep sea is. Then explain that the anglerfish's light is lit by its "bacterial friends". Showing a child that nature is full of helping partnerships — even a single fish carries friends on board — is a lovely lesson.