Branches full of tiny animals
A red sea fan can have red, purple or yellow branches. Look closely and you’ll see tiny animals called polyps. Each has a mouth surrounded by eight feathery tentacles. They catch tiny animals and scraps of food drifting past, even in the shade where fewer seaweeds grow.
The current brings dinner
Water brings tiny animals, eggs and bits of food. A polyp spreads its tentacles and grabs whatever drifts close enough. Tiny stinging cells help it hold its catch. When the water barely moves, food arrives slowly. When it rushes past, it can be hard to hang on.
A fan facing the current
Think of a sieve under a tap. Hold it flat and water runs through the holes. Turn it on edge and more of the water misses it. A sea fan can face the current with its broad side. Scientists found that one kind caught more food that way. Its branches can bend as the water pushes past.
