Astropecten polyacanthus

Acclimation: it does not tolerate sudden changes in oxygen, salinity and pH. Acclimate it gradually by drip and never expose it to air.

Setup: an established tank with a sand bed several centimetres deep to bury in. It is mostly nocturnal and moves a lot of sand.

Tankmates: it leaves corals alone (LiveAquaria calls it reef compatible), but it is a predator: it eats small shrimps, urchins, molluscs, bivalves and small sea stars. So it does not belong with a snail clean-up crew or small invertebrates. Being slow, it must not share the tank with its predators, such as pufferfish.

Starvation: a voracious feeder, it quickly clears the tank of detritus, then burrows, starves and decays in the substrate if not fed. If the tank is overstocked with them, they starve. Sensitivities: no copper. Toxin: TTX is documented through ingestion (the food chain); none of the sources consulted describes poisoning from mere contact.

Water: aim for 22 to 25.5 °C, a specific gravity of 1.023 to 1.025, pH 8.1 to 8.4 and 8 to 12 dKH.

In the wild it mostly eats bivalves and gastropods, which it swallows whole, as well as other small buried invertebrates and detritus.

In the aquarium it eats detritus and leftover food, but also small shrimps, urchins, molluscs and small stars. Feed it actively with a varied diet of live or frozen meaty foods, especially in an established tank, so it does not starve once the sand is clean.