Astraea tecta Snail
Lithopoma tectum
The Astraea Snail is a hardworking member of a marine aquarium clean-up crew, known for its distinctive conical shell, pronounced ridges and steady appetite for algae.
Often seen making its way over live rock and aquarium glass, this peaceful snail grazes on diatoms and soft films of microalgae. Its unhurried movement hides a useful daily routine: constantly searching the reef for its next feeding surface.
Although the name Astraea tecta remains popular in the aquarium trade, the accepted scientific name is Lithopoma tectum, also called the West Indian Starsnail. The species is native to rocky reefs and coastal habitats of the Caribbean and western Atlantic.
Unlike sand-sifting snails, Astraea Snails concentrate on hard surfaces. They can help keep glass and rockwork cleaner without consuming healthy coral tissue or deliberately disturbing other reef inhabitants.
An important care consideration is that these snails may struggle to right themselves if they fall upside down on open sand. Helping an overturned snail back onto its foot can make a real difference to its survival.
With sufficient natural algae, plenty of established rockwork and stable reef conditions, this attractive little grazer is a valuable part of a balanced marine aquarium.
Feeding Notes
Astraea Snails are herbivorous grazers that feed predominantly on microalgae, diatoms and soft algal films growing on glass, live rock and other hard surfaces.
Provide an established aquarium with sufficient natural algae. These snails do not sift sand or consume detritus as their main food, and should not be expected to eliminate every type of nuisance algae.
In very clean aquariums, small amounts of dried marine algae such as nori, or a suitable invertebrate herbivore food, may be offered on an accessible rock or feeding clip. Remove uneaten food before it deteriorates.
Avoid adding more grazing snails than the aquarium can support. An Astraea Snail can slowly starve when surfaces become too clean, even while other inhabitants appear healthy.
Observe that the snail is regularly moving, gripping surfaces and grazing. Prolonged inactivity or repeated falls can indicate a problem.
Astraea Snails are most effective against thin films and developing algae, rather than heavy infestations of long hair algae.
Aquarium Setup Notes
Provide a mature and stable marine aquarium of around 60 litres or larger, with ample rockwork and algae-bearing hard surfaces. The number of snails should reflect available grazing, not a fixed stocking formula.
These snails are naturally associated with rocky reef and rubble environments. They need stable footholds and routes between rockwork and glass.
Important: check for overturned snails. An Astraea Snail may be unable to turn itself upright after falling onto open sand. Gently position an overturned snail foot-down against rockwork so it can reattach.
Maintain stable marine water conditions, typically 23–26 °C, pH around 8.1–8.4 and specific gravity approximately 1.023–1.026. Avoid abrupt changes during transfers or maintenance.
Moderate general water movement and good oxygenation are suitable, provided the snail can graze without being dislodged by a concentrated pump outlet. Standard reef lighting is suitable.
Acclimate gradually when moving between aquariums with different salinity or temperature, and avoid adding transport water to the display aquarium.
Normal reef calcium and alkalinity maintenance helps support shell growth. Do not add supplements without testing and an identified need.
Avoid copper-based medicines and confirm all aquarium treatments are safe for marine gastropods.
Compatibility Notes
Astraea Snails are peaceful, reef-safe invertebrates that can live alongside suitable marine fish, corals and other non-predatory clean-up crew animals.
Reef safe: They graze algae from hard surfaces rather than healthy coral tissue, making them generally suitable for soft coral, LPS and SPS reef aquariums.
They can coexist with peaceful shrimp, other snails and suitable hermit crabs when food and shelter are adequate. Competition for algae can become a problem in very clean or densely stocked aquariums.
Avoid fish that prey on snails or crush shells, including many puffers, triggerfish and some large predatory wrasses.
Some hermit crabs may attack a living snail or take its shell, particularly when the snail is weak, overturned or otherwise unable to retreat.
A moving snail can occasionally knock loose, unsecured coral frags. Secure delicate frags and check that grazing routes are unobstructed.
Check snails regularly on open sand and around the base of glass panels, and return overturned individuals to a stable surface.
Use Astraea Snails as part of good reef husbandry, not as a substitute for appropriate nutrient control and regular maintenance.