Sand star (Astropecten polyacanthus) care guide

Group

Other invertebrates

Other names

Sand star, Sand sifting sea star, Comb sea star, Sand sifter, Sand sifting starfish

Family

Astropectinidae

Origin

Indo-Pacific, from the Red Sea and Zanzibar to Hawaii and from Japan to Australia and New Zealand, on silty sand to about 185 m

Water

saltwater

Maximum size

20 cm

Temperature

23–27°C

pH

8.1–8.4

Hardness

dKH 8–12, SG 1.023–1.026

Minimum tank

300 litres

Care level

intermediate

Temperament

peaceful

Reef safe

with_caution

Lifespan

2–5 years

Care

The sand sifting starfish is the most widely spread Astropecten in the Indo-Pacific, with an arm span up to about 20 cm. Its upper surface is dark purplish with cream, grey or brown plates, sometimes in a chevron pattern, the underside is orange, and a fringe of long sharp spines runs along the arms. Its tube feet are pointed for digging rather than sucker-tipped, so it cannot climb glass like other starfish. Archaster sand stars look similar but have flat, blunt spines. Set-up: it needs a large tank, 300 litres or more, with a deep, mature sand bed covering most of the floor. It spends much of its life buried and comes out mostly at night. Water figures here are general reef guidance rather than from a source. Aim for 23–27 °C, pH 8.1–8.4, dKH 8–12, stable SG 1.023–1.026. Acclimatise very slowly by drip. Clean-up crew: it clears detritus and uneaten food from sand, but it also swallows small molluscs and sand-bed life whole, and it eats the worms, pods and other creatures that keep a sand bed healthy. In smaller tanks it strips the sand bed and then starves. Keep only one, and only where the sand bed is large. Toxins: this species contains tetrodotoxin, a potent nerve toxin. It is not dangerous to handle normally, but do not let pets eat one, and wash hands after handling. Copper: copper-based medicines and some plant fertilisers are toxic to shrimp, snails and most other invertebrates. Never treat a tank holding them with copper, check the label of any fertiliser or medicine, and keep nets and buckets used for copper-treated tanks separate. Sources: Wikipedia (en.wikipedia.org/wiki/Astropectenpolyacanthus). Checked October 2026.

Diet

Eats detritus and bivalve and gastropod molluscs, swallowing them whole, plus worms and small invertebrates in the sand. It sometimes engulfs pebbles to digest the film on them. In aquariums target-feed by burying a pellet or piece of shrimp or mussel near it a few times a week once the sand bed has been worked over.

Breeding

Not bred in aquariums. Sexes are separate and it spawns into the water with planktonic larvae.

Compatibility and tank mates

Harmless to corals and fish, but it eats nassarius and other small snails, small clams, sand-bed worms and pods. Do not keep with sand-sifting gobies or other sand stars competing for food. Puffers, triggers and harlequin shrimp may attack it.

Last updated 8 October 2026. Community-edited care guide on Aquatic-Auctions.