Spiny Star Astraea

Quick facts

Identity

Also known as

Spiny Star Snail; Star Astraea Snail

Synonyms

Lithopoma phoebia

Environment

Saltwater

Native to

Gulf of Mexico, Caribbean, western Atlantic

Habitat

Shallow intertidal and nearshore rocky areas where algae and diatom-covered rock and rubble accumulate

Sourcing

Wild-caught

Conservation

Not Evaluated

Care

Care level

Easy

Temperament

Peaceful

Adult size

0.5 – 1 in (1.3 – 2.5 cm)

Lifespan

2 – 5 yrs

Min tank

20 gal (76 L)

Growth rate

Slow

Placement

Bottom, Rock & glass

Water

Temperature

72 – 78 °F (22 – 26 °C)

pH

8.1 – 8.4

dKH

8 – 12 dKH

Salinity

1.023 – 1.025 SG

Flow

Low-Moderate

Behavior & compatibility

Social

Solitary

Aggression to own kind

Low

Active

Night

Reef safe

Yes

Invert safe

Yes

Shrimp safe

Yes

Clean-up role

Algae, Biofilm

Population boom risk

Low

Feeding & breeding

Diet

Herbivore

Foods

Algae, Vegetables, Wafers

Breeding type

Broadcast spawner

Breeding difficulty

Not bred in captivity

Sexing

Sexes cannot be distinguished externally; not practical to sex in the aquarium trade

Target feeding

Beneficial

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Care guide

Overview

A pyramid-shaped shell with green, yellow, and tan tones bears pronounced sculptured spiral ridges that flare into star-like points. This slow, nocturnal grazer patrols rock and glass for hair algae, cyanobacteria, and diatoms in reef and fish-only tanks alike. It needs stable water quality, copper-free medication, and a substrate it can right itself on if flipped.

Care

This snail is a hardy, easy-to-keep grazer suited to established reef and fish-only marine tanks with rockwork to patrol. It spends most of its time moving over live rock and glass rather than climbing, so it is best kept in tanks with a sandbed or solid substrate it can right itself on if it falls. Sudden shifts in salinity, pH, or nitrate are poorly tolerated, so stable, mature water conditions matter more than with many other snails. Copper-based medications will kill it, so it should be removed before any copper treatment is dosed in the system.

Feeding

Diet consists mainly of hair algae, cyanobacteria, and diatom films grazed from rock and glass surfaces. In tanks without enough natural algae growth, supplement with blanched spinach, lettuce, dried seaweed, or algae wafers so the snail does not starve. A single individual per five gallons is a reasonable stocking guideline to keep the algae supply matched to the population.

Tank mates

Peaceful and unable to harm corals, fish, or other invertebrates, making it compatible with nearly any reef or fish-only community. Its small size and slow movement mean it rarely knocks over frags, unlike some larger snail or hermit crab species. Avoid pairing it with aggressive crabs or large predatory fish that may attack or flip it, since it struggles to right itself once overturned.

Breeding

Not known to reproduce in home aquariums, as this species requires a planktonic larval stage that develops in open ocean conditions. Any offspring seen in captivity are essentially unheard of, so ongoing stocking relies entirely on wild collection. No sexual dimorphism has been documented that would allow hobbyists to pair breeders even if spawning were attempted.

Health

The main risk is a snail flipping upside down and being unable to right itself, which can lead to starvation or death if not noticed and corrected promptly. High nitrate levels are poorly tolerated and can shorten lifespan even though the snail is otherwise considered hardy. Any exposure to copper-based medications used to treat fish disease is lethal and should be strictly avoided.

Sources

1. Spiny Star Astraea (Ninja Star Snail) - LiveAquaria
2. Spiny Star Astraea (Astraea phoebia) - The Aquarium Wiki
3. Star Snail, Spiny Star Astraea Snail - Saltcorner
4. Spiny Star Astraea - Reefs.com

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