Nerite Snail

A nerite suits any cycled, established tank with algae and biofilm to graze, and even a small tank of about 20 litres can support one, scaling up to one snail per 20 to 40 litres to match the food available. They need harder, alkaline water and a calcium source for shell health, plus plenty of algae covered surfaces. Fit a secure lid, as nerites are accomplished climbers that will wander out of an open tank.

Nerites graze naturally on algae and biofilm, but in a clean or newly stocked tank there may not be enough to sustain them, so supplement with algae wafers and blanched vegetables such as courgette and spinach. Provide a calcium source such as a cuttlebone or mineral supplement to keep the shell strong. They are grazers rather than scavengers, so they will not clear up leftover protein or waste.

Keep the water at 22 to 28 degrees Celsius, pH 7.0 to 8.5, and moderately hard to hard with calcium available, because soft, acidic water erodes and pits the shell. The tank must be fully cycled with ammonia at 0 and nitrite at 0, as nerites are very sensitive to ammonia. Dechlorinate tap water, and crucially never use copper based medications or plant fertilisers, which are toxic to snails and other invertebrates.

Nerites are not social in a herd sense but are entirely peaceful and community safe, coexisting with fish, shrimp, plants and each other without trouble. Stock roughly one per 20 to 40 litres so there is enough algae to go round. They will lay small, hard, white eggs like sesame seeds on surfaces and decor, which are harmless and simply will not hatch in freshwater, so no population control is ever needed.

Plenty of algae and biofilm covered glass, rocks and driftwood keep a nerite busy and well fed, and a mature, established tank suits them far better than a brand new one. Smooth grazing surfaces and gentle flow let them roam and feed naturally across the whole aquarium.