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, now classified as Vittina natalensis and long known as Neritina natalensis, is a small algae-grazing snail from the east coast of Africa, where it lives in coastal lagoons, estuaries, and mangrove fringes from the Jubba River mouth in Somalia south through Kenya and Tanzania to Mozambique and South Africa. The species name points to the old province of Natal. It belongs to the family Neritidae, and in the hobby the label nerite snail is spread across several genera, including Clithon, the horned nerites, and other Vittina such as the red racer, V. waigiensis, all with broadly similar care. Adults shrug off a wide range of salinity, from fresh water up to roughly full seawater, which is why they do well in a freshwater tank. The catch for breeders is the life cycle: they will readily lay hard white egg capsules on glass, rock, wood, and equipment in fresh water, but the larvae are marine and need brackish or salt water to develop, so the eggs never hatch in a freshwater aquarium. That is exactly why nerites are prized, since they graze algae hard without breeding into a plague. They are among the best algae eaters in the hobby, clearing diatoms, green spot algae, and biofilm without touching healthy plants.

Breeding

Nerites cannot reproduce in a freshwater tank. A female still lays hard, sesame-seed-sized white egg capsules cemented onto glass, wood, rock, equipment, and even other snails' shells, but the larvae are planktonic veligers that need brackish or salt water to develop, so nothing hatches in fresh water. The capsules are purely cosmetic, easy to scrape off glass and stubborn on wood and rock. Actually raising young means moving eggs to brackish water and rearing them through the marine larval stage, which is difficult and rarely attempted. This inability to breed in fresh water is the main reason nerites are so popular: algae control with no population explosion.

Common problems

The two recurring gripes are eggs and shells. The infertile white capsules get stuck to everything and resist removal except with a blade on glass. Shells erode in soft, acidic water, thinning and pitting until the snail dies, so the tank needs at least moderate hardness and a pH around or above neutral. Newly added nerites sometimes land upside down and cannot right themselves, so a flipped snail is worth turning over, and some refuse to settle and feed in a sparse new tank and slowly starve, with no real fix beyond making sure there is algae for them to graze.

Bioload

Further reading

• Blackwater tanks: replicating acidic jungle streams
• Medicating a tank with snails and shrimp
• Algae: what kind you have and how to fix it