Nerite Snail
Nerita spp.
The glass specialist — small and reef-safe, it scrapes film algae and diatoms off the panes.
Difficulty: BeginnerCleanup crewReef-safe
The nerite snail (Nerita spp.) is a small, tough glass-cleaning specialist — it clings to the panes and scrapes off the film algae and diatoms other snails miss, tirelessly and without ever bothering a coral. The only quirk you'll notice is the tiny white eggs it sometimes dots around the tank: harmless, and they almost never hatch in captivity.
Care at a glance
| Adult size | Small — usually under 1 in (rarely to ~1.5 in). |
|---|---|
| Minimum tank | Any tank, including nanos; roughly 1 per 5 gallons. |
| Temperature | 75–82°F (24–28°C). |
| pH | 8.1–8.4. |
| Specific gravity | 1.023–1.026 (reef-standard ≈35 ppt). |
| Other targets | Standard reef calcium and alkalinity keep the shell healthy; like all inverts it has zero tolerance for copper. |
| Diet | Film algae, diatoms, and some filamentous algae and cyanobacteria — especially on the glass. |
| Temperament | Peaceful and fully reef-safe; a dedicated glass grazer. |
| Reef-safe | Yes, completely — it only grazes algae. |
| Natural range | Wide-ranging (Indo-Pacific and Atlantic species). |
The fish store gets these wrong
Common myths, kindly corrected — no shame for having believed them.
- "The white dots are a pest or disease." They're nerite eggs — harmless, and they almost never hatch in a saltwater tank.
- "Nerites clean the whole tank." They're glass and film-algae specialists — pair them with grazers and scavengers for rock and sand.
Before you buy
- A cycled tank; drip-acclimate; never any copper.
- A lid or slightly lower water level (they can climb out).
- Rock and sand cleaners alongside for full coverage.
Signs something's wrong
A struggling invert is usually telling you about water quality, acclimation, or (for shrimp and crabs) a fresh moult — here's what to watch for:
- Above the waterline or escaped — they wander up; keep water topped down or lidded.
- Empty shell — died from a swing, copper, or an un-cycled tank.
Never
- Never worry about the white eggs — they're harmless.
- Never add to an un-cycled tank, dose copper, or drop it straight in.
Common nerite snail questions
What are the little white dots my nerite snail leaves?
Eggs — nerites lay small white egg capsules on glass and rock. They're completely harmless and almost never hatch in a saltwater aquarium, because the larvae need particular brackish/marine plankton conditions to develop.
Are nerite snails reef-safe?
Yes, completely — they graze film algae and diatoms and never touch corals.
What do nerite snails eat?
Film algae, diatoms, and some filamentous algae and cyanobacteria — especially off the glass, which they clean better than most snails.
Do nerite snails climb out of the tank?
They can wander above the waterline, so keep the water topped down a little or use a lid — a nerite that dries out won't recover.
How many nerite snails do I need?
About one per 5 gallons for glass duty; pair them with rock grazers and sand scavengers so every surface is covered.
Sources & further reading
This guide was written and fact-checked against these authorities. It's honest, general guidance — not a diagnosis, and not a substitute for an aquatic vet or your own test kit:
- Pod Your Reef — Saltwater Snails for Reef Tanks — glass-algae role, size, diet
- Top Shelf Aquatics — Clean Up Crew Species Guide — film-algae specialist, care
Written and fact-checked by The Coralkin Team against marine-aquarist sources — if your nerite snail is struggling, it's almost always water quality, acclimation or a moult — check those first and ask an experienced reefer. We never guess a care number.
🔬 Review status: team-written and fact-checked against cited sources · not yet reviewed by a marine vet. How we research & fact-check →