A classic reef glass-and-rock grazer with a distinctive low, star-edged conical shell — the 'astrea' or West Indian star snail. It is one of the best snails for film and hair algae on glass and live rock, but its near-flat shell makes it notoriously bad at righting itself if it falls onto the sand, where it can die stranded on its back.
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Educational only. KinStation content is reviewed by licensed veterinarians but cannot replace an in-person exam. Always consult a licensed veterinarian or board-certified specialist for diagnosis, treatment, or any decision affecting your pet's health.
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Conical, star-edged shell to about 6 cm (2.5 in); typically smaller in the trade.
Lifespan
1–3 years
Social needs
group
Native region
Western Atlantic and Caribbean (Gulf of Mexico and Lesser Antilles to Brazil)
Origin
New World
Climate
⛅ Subtropical
Water type
🌊 Marine
Family
Turbinidae
Genus
Lithopoma
Part of the Marine Snails
Grazing and detritivore snails kept as reef-safe cleanup crew. Different species specialize in glass and rock algae, sand-bed detritus, or leftover food; stock to match available food, keep copper at zero, and acclimate slowly since snails are very sensitive to salinity shifts.
How this animal changes through its life — each stage often has its own care, diet and space needs.
Photo coming soon
Larva
Most marine invertebrates hatch into microscopic planktonic larvae (such as the zoea of crustaceans or the bipinnaria/veliger of echinoderms and mollusks) that drift and feed in the water column. The larva looks nothing like the adult and undergoes major reorganization.
Photo coming soon
Juvenile
After settling out of the plankton, the juvenile takes on a recognizable miniature of the adult body plan — a tiny shell, a small star, or a translucent shrimp. Crustaceans grow by molting, shedding the exoskeleton to enlarge.
Photo coming soon
Adult
Adults reach full size and reproductive maturity with the species' mature shell, shape, or coloration. Many continue to molt or grow throughout life, and some show sex differences in size or claw/appendage shape.
Color & pattern variants
Natural variants occur in the wild; selectively bred (man-made) variants were developed in captivity.
Natural
West Indian Star (typical)
The usual form: a low conical shell with a star-like scalloped or knobbed margin, in reddish-orange with white and olive patches, often algae- or coralline-encrusted. A natural species, not a bred strain.
Habitat & enclosure
Keep a small group in an established reef or FOWLR tank of 10-20 gallons (38-75 L) or more with plenty of algae-covered live rock and glass to graze. Maintain stable reef parameters: temperature 72-80F (22-27C), pH 8.1-8.4, salinity SG 1.024-1.026, alkalinity 8-11 dKH, calcium 400-450 ppm and low nitrate with zero ammonia/nitrite.
Lithopoma tectum is a western-Atlantic and Caribbean species, found from the Gulf of Mexico and Lesser Antilles to Brazil in shallow rocky and reef habitat. Any reef lighting and moderate flow suit it; it spends almost all its time grazing vertical rock and glass rather than sand.
Substrate
This is a rock-and-glass grazer, so abundant algae-covered live rock matters far more than substrate; any sand or bare-bottom base works underneath. Because it self-rights poorly, smooth open sand expanses where it can topple onto its back are a hazard worth watching.
Equipment & setup
Standard marine equipment is enough: live-rock biofiltration, a heater, a protein skimmer and moderate flow. No special lighting is required; keep calcium and alkalinity stable to protect the shell.
Diet
A dedicated herbivore that grazes film algae, hair algae, diatoms and some cyanobacteria off glass and live rock, keeping vertical surfaces clean. It is a surface specialist, not a sand sifter. In a low-algae tank it will run short of food and slowly starve, so supplement with dried seaweed (nori) on a clip if algae is scarce.
Behavior & temperament
Peaceful and fully reef-safe toward fish, corals and other inverts; it simply mows algae off rock and glass. Its one notable downside is mechanical: the low star-shaped shell leaves it poor at self-righting, so an astraea that falls or is knocked onto its back on open sand often cannot flip over and may die there. Stock several to make a real dent in algae and check the sand for stranded snails.
Health
Extremely sensitive to copper, salinity and temperature swings and air exposure like all marine snails — never use copper meds, drip-acclimate slowly and never lift it into the air. The biggest avoidable killer is being left stranded upside-down on the sand, so periodically right any you find on their backs. Eroding shell tips indicate low calcium/alkalinity; starvation strikes in spotless tanks. Remove any dead snail promptly to avoid fouling. (Educational only, not a substitute for advice from an aquatic veterinarian.)
Tips, DIY & hacks
Buy astraeas in groups and stock to algae availability, not water volume. Drip-acclimate slowly and never expose them to air. Check the sand bed regularly and flip any stranded on their backs, since they struggle to right themselves. Excellent for film- and hair-algae on glass; pair with a sand-sifting cerith or conch for substrate cleanup.
Reviewed and signed off by: KinStation Editorial — pre-launch draft (pending DVM review) on 2026-06-10