Nerite snail

Overview

Nerite snails (Neritina natalensis and relatives) are the go-to algae-eating snail — patterned in zebra, tiger, horned and olive forms, and famous for grazing tough algae films that defeat other cleaners. Best of all, they cannot breed in a freshwater tank, so unlike pest snails they never overrun the aquarium. Peaceful, hard-working and attractive, they’re a near-perfect cleanup snail. Because they stay small and never multiply out of control, you can add exactly the number your algae supply supports and trust the population to hold steady for the life of the tank.

Tank & water

A 19 litre (5 gallon) tank is enough for one or two. Nerites prefer harder, more alkaline water than shrimp:

• A cycled tank — cycle fully; they still dislike ammonia and nitrite.
• Harder, alkaline water — pH above 7 and some hardness keep their shells healthy; soft acidic water erodes shells.
• Calcium — hardness and mineral supplementation prevent pitted, thinning shells.
• No copper — copper in some medications and fertilisers harms snails and shrimp; check labels.

Feeding

Nerites are algae grazers first and foremost, and a tank with steady algae growth may feed them entirely. In a very clean tank supplement with algae wafers, blanched vegetables or a quality sinking food so they don’t starve — a snail that has cleared all the algae still needs feeding. A common mistake is adding too many nerites to a small, spotless tank, where they strip the last algae quickly and then slowly starve, so match snail numbers to how much algae your tank actually grows.

Tankmates & breeding

Nerites are entirely peaceful and mix with almost any community fish, shrimp and other snails. Avoid known snail-eaters such as loaches and pufferfish, and the assassin snail. They won’t breed in freshwater, so a group stays stable — add snails to match your algae, not the other way around.

Compare with the pest-eating assassin snail and the larger mystery snail.