Nerite snail

Water parameters

Tolerated range for this species. Aim for the middle of each band rather than the extremes.

Tank and habitat

Substrate: any.

Behavior

Plant interaction: plant safe.

Typically wild-caught; acclimate slowly.

Feeding

Primarily algae grazers. They rasp hard algae off glass, rocks, and plant leaves using a toothed radula. In a tank with limited algae growth, supplement with algae wafers. They also eat biofilm on driftwood and decaying plant matter. Do not rely on nerites as the sole algae control; a single nerite can keep a 60 L tank's glass clean, but they won't prevent algae problems caused by excess light or nutrients. They graze constantly and slowly, working a systematic path across surfaces.

Nocturnal feeder; drop food after lights out.

Compatibility

• Safe with everything. No fish or shrimp is threatened by a nerite snail.
• Assassin snails will kill nerites. Do not keep together.
• Loaches (clown loach, yoyo loach) and puffers eat snails. Nerites are not exempt.
• Nerites sometimes climb out of the tank. A lid with minimal gaps is recommended. Finding a nerite on the floor is a common experience.

Origin and habitat

The zebra nerite (Vittina natalensis, formerly Neritina natalensis) is native to eastern Africa, found in freshwater lagoons and mangrove swamps along the coast from Somalia's Jubba River mouth south through Kenya and Tanzania to Mozambique and South Africa's KwaZulu-Natal. The species name natalensis refers to the old province of Natal in South Africa. A member of the family Neritidae. In the aquarium trade, "nerite snail" is a catch-all label applied to several species from different genera, including Vittina waigiensis (red racer/gold racer nerite, from the Philippines and Indonesia) and Clithon species (horned nerites from Southeast Asia); these are different species with different native ranges, though care is similar. The key feature for aquarists: nerite snails lay small white egg capsules on hard surfaces in freshwater, but the larvae require brackish water to develop, so eggs will not hatch in a freshwater tank. This prevents population explosions but leaves small white dots on glass and decor that must be scraped off. Among the most effective algae eaters in the hobby: they clear diatoms, green spot algae, and biofilm without damaging healthy live plants. Known to climb above the waterline; a tight-fitting lid is recommended. Shell health requires adequate mineral content in the water; soft, acidic conditions erode shells over time.

Breeding

Cannot reproduce in freshwater. Females lay small white eggs (hard, sesame-seed-sized) on hard surfaces: glass, wood, rocks, equipment, and other snails' shells. The eggs are extremely difficult to remove and do not hatch in freshwater. They are purely cosmetic annoyance. Actual reproduction requires brackish water, and raising larvae through the planktonic veliger stage is difficult. This non-breeding trait is why nerites are popular: they clean algae without creating a population explosion like pest snails do.

Common problems

Egg deposits on decor and glass. Nerites lay infertile eggs on everything and they're cemented in place. A razor blade removes them from glass; on wood and rock you're mostly stuck with them. Shell erosion in soft acidic water: nerite shells dissolve slowly in water below pH 7.0 or KH below 3. The shell thins, pits, and eventually the snail dies. Maintain at least moderate hardness. New nerites sometimes flip over and can't right themselves; place them right-side-up if you find one on its back. Some nerites refuse to eat in a new tank and slowly starve; there's no reliable fix other than ensuring the tank has ample algae growth.

Bioload

Further reading

• Stocking ideas by tank size