Green Brittle Star

Care at a glance

Overview

It needs a large tank of 300 litres or more at 24 to 27 C and pH 8.1 to 8.4 with heavy rockwork to hide in. It is hardy and easy to feed on chunks of shrimp, mussel, or fish dropped near its arms. The catch is that a large one will hunt and eat small fish, shrimp, and other brittle stars at night, so treat it as a predator and keep it away from small gobies, cardinals, and ornamental shrimp.

In the wild

This is a large green brittle star with a disc a couple of centimeters across and five long flexible arms that can span 40 cm or more. It hides in the rockwork by day with just an arm tip showing and comes out to feed after dark. The green coloring often carries a faint banded pattern down the arms.

Good to know

Ophiarachna incrassata is unusual among brittle stars because it is an active predator, not just a scavenger. It has been recorded arching its body into a dome to trap small fish and then dropping down on them.

Did you know

It hunts by curling its arms into a raised dome to lure and shelter sleeping fish underneath, then collapses onto them to feed.

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