Sea Angel - a dangerous predator with a surreal beauty that seems to only exist in fairy tales

The sea angel is a beautiful creature under the ocean but a fearsome predator. Here are some interesting facts about the sea angel .

Sea angels are tiny, nearly transparent sea slugs with wing-like appendages that live in oceans around the world.

They are quite small in size, the largest being only about 7cm long, while many are under 2cm. Without their 'wings' they look very much like common land slugs.

Despite their cute appearance, they are actually quite dangerous predators. Their favorite food is other snails including sea butterflies, their close relatives that live in snail shells.

The sea angel can glide across the water at a speed of 10cm/s, almost as fast as a goldfish. This speed is enough to help this strange creature easily surpass its prey. Not only relying on speed, the sea angel also has another unique way of hunting, the opposite of chasing is waiting. It makes its prey do all the work and becomes the laziest predator in the world.

Normally, sea butterflies use the mucus secreted from their feet to catch plankton. Then, when it is time to eat, they eat the prey attached to the mucus. The concept and function of the sea butterfly's mucus is similar to that of a spider web. But when the sea butterfly encounters the prey of the sea angel in the mucus, the situation turns around and the sea angel becomes the hunter.

In most animals, hunting is very energy-intensive, but sea angels use passive hunting techniques that save energy while still getting food.

The Difference Between Sea Angels and Sea Butterflies

Sea angels and sea butterflies are both pteropods—sea snails and sea slugs that swim. Sea angels, or Gymnosomata (meaning 'naked bodies'), do not have shells. Sea butterflies (Thecosomata) are usually smaller and have shells.

What species do sea angels eat?

Sea angels are an important food source for a number of animals including jellyfish, ctenophores, fish, baleen whales and birds. In the murky waters of the deep sea, the transparent bodies of sea angels help them hide from predators.

How do sea angels reproduce?

Clione are hermaphrodites, meaning they have both male and female reproductive organs. During mating, individuals will come together for several hours and fertilize each other. After fertilization, the sea angel will lay eggs in a free-floating ball.

Samuel Daniel

Update 08 January 2025