Cerith snail (Cerithium atratum) care guide

Group

Snails

Other names

Dark cerith, Florida cerith, Murex atratus, Cerithium floridanum, Cerithium antillarum

Family

Cerithiidae

Origin

Western Atlantic and Caribbean, intertidal to 91 m

Water

saltwater

Maximum size

3.8 cm

Temperature

22–26°C

pH

8.1–8.4

Hardness

dKH 8–12, SG 1.023–1.025

Care level

beginner

Reef safe

yes

Care

Cerithium atratum is a small marine snail with a tall, slender, spiralled shell, sold as the cerith snail. It comes from the western Atlantic and Caribbean, from the shore down to about 91 m, and has many synonyms, including Cerithium floridanum. LiveAquaria sells ceriths from the Caribbean and the eastern Pacific off Mexico under Cerithium sp. and lists a maximum size of about 3.8 cm. Keep it in a mature reef or marine tank, ideally with a sand bed. LiveAquaria notes it does best in larger, established systems with deep sand beds. Water: 22–26 °C, pH 8.1–8.4, dKH 8–12, SG 1.023–1.025. It is sensitive to nitrate spikes and sudden changes, so drip-acclimatise it. Clean-up role: ceriths eat film and hair algae, diatoms, detritus, fish waste and leftover food, and they burrow, which stirs and aerates the top of the sand bed. They are mainly active at night. One per 20–40 litres is a common guide. Ceriths also clean the glass at the waterline and the sand surface that turbo snails miss. When the algae is gone they can starve, so feed algae wafers if they run short. Copper: copper-based medicines and some plant fertilisers are toxic to shrimp, snails and most other invertebrates. Never dose them in a tank holding this animal, and check the label of any treatment or fertiliser before use. Sources: LiveAquaria (liveaquaria.com/products/cerith-snail); Wikipedia (en.wikipedia.org/wiki/Cerithiumatratum). Checked October 2026.

Diet

Omnivorous grazer and scavenger: film algae, diatoms, hair algae, detritus, fish waste and leftover food. It may also graze some cyanobacteria. Supplement with algae wafers or dried seaweed if algae runs short.

Breeding

Separate sexes, which are hard to tell apart. Pairs lay stringy egg strands on the glass after dark, but the eggs are usually eaten by tankmates or taken up by filters. The larvae are planktonic, so breeding in captivity is very difficult, and the conditions needed are unknown.

Compatibility and tank mates

Reef safe: does not harm corals, fish or other invertebrates. Eaten or attacked by hermit crabs (especially if there are no spare shells), larger crabs, triggers, puffers, some wrasses and predatory snails.

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