Sand-sifting star

Care at a glance

Overview

The sand-sifting star is a peaceful, reef-safe sea star that spends its time on the bottom of the tank. It is easy to keep, given a big enough sand bed.

Caring for the sand-sifting star

Keep a sand-sifting star in a large, mature tank of at least 53 gal (200 L), with a deep, well-stocked sand bed. That gives it enough sand surface to forage without stripping the bed bare. Give it soft, fine to medium sand at least 5 to 8 cm deep. Leave plenty of open sand rather than a rock-choked aquascape, since it depends on the sand bed for both shelter and food.

Hold the water at 75 to 81°F (24 to 27°C) and a pH of 8.1 to 8.4, and keep the salinity stable. A sudden swing in specific gravity or pH can kill it outright. Like every sea star, it needs a slow drip acclimation. Never lift it out of the water or expose it to air while moving it.

The sand-sifting star feeds on detritus, uneaten food, and the worms, copepods and other microfauna living in the sand. It cleans and aerates the top layer of substrate as it burrows. In a small tank, one star can strip a modest sand bed of its microfauna within months, then slowly starve once the food runs out.

It is reef safe and uninterested in corals. Pairs mate through pseudocopulation, with the male climbing onto the female and riding on top of her, sometimes for weeks. He synchronizes his spawning with hers, and they release eggs and sperm together.

Good to know

The sand-sifting star, Archaster typicus, belongs to the family Archasteridae. The trade often confuses it with the similar-looking Astropecten polyacanthus. That sand star swallows small mollusks whole and carries the nerve toxin tetrodotoxin in its tissues. A true Archaster typicus has blunt, flattened spines and suckered tube feet. Astropecten has sharper spines and pointed, non-suckered tube feet built for digging rather than gripping.

In the wild

The sand-sifting star lives on shallow sand flats, seagrass meadows and lagoon shallows across the Indo-Pacific, often right in the intertidal zone. Its range runs from the Maldives and East Africa to Japan and Hawaii, and south to Australia and New Caledonia. It moves over and just beneath the sand surface, sifting through the top layer as it forages.

Common questions

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