Batman nerite (Septaria porcellana) care guide

Group

Snails

Other names

Turtle nerite, Porcelain nerite, Navicella porcellana, Septaria suborbicularis, Sandalium pictum, Shield nerite

Family

Neritidae

Origin

Streams of India, the Philippines, Indonesia, New Guinea and New Caledonia, from near the sea to 5–6 km inland

Water

freshwater

Maximum size

1.3 cm

Temperature

22–28°C

pH

7–8.2

Hardness

6–12 dGH, 4–8 dKH

Minimum tank

20 litres

Care level

intermediate

Care

The batman or turtle nerite is a tiny freshwater nerite with a flat, cap-shaped shell rather than a coiled one, so it looks like a miniature limpet or turtle shell. The shell is yellow-brown with a black or pinkish-purple pattern of triangles and lines, often forming a bat-like mark, and grows to about 1.3 cm. Underneath, a narrow internal shelf (septum) gives the genus its name. Males are usually smaller than females. Tank set-up: in the wild it clings to stones in both still and fast-flowing streams, from close to the sea to several kilometres inland, so it likes clean, well-oxygenated water with some current and plenty of smooth rocks and wood to graze. A mature tank of 20 litres or more with stable water suits it. Keep the water hard enough to protect its shell. Handling: it clamps down very tightly. Never pull or prise it off a surface, as this can tear its foot; wait until it moves, or slide a thin card gently underneath. Make sure filter intakes are covered. Water: tropical, about 22–28 °C, with neutral to slightly alkaline pH and moderate hardness. Soft, acidic water erodes nerite shells. Role: an excellent algae grazer that cleans film algae and diatoms from rocks, wood and glass without harming plants. It may starve in a brand-new or very clean tank, so add it to a mature tank and supplement with algae wafers if needed. Copper: copper-based medicines and some plant fertilisers are toxic to shrimp, snails and most invertebrates. Never dose them in a tank holding this animal, check the label of any treatment or fertiliser, and use a separate hospital tank for fish. Sources: Wikipedia (en.wikipedia.org/wiki/Septariaporcellana). Checked October 2026.

Diet

Grazes soft film algae, diatoms and biofilm from hard surfaces. In a tank with little algae, offer algae wafers, spirulina tablets and blanched courgette or spinach. Does not eat healthy plants.

Breeding

Sexes are separate. Like other freshwater nerites, it is expected to lay small white egg capsules on hard surfaces in fresh water that do not hatch there, because nerite larvae normally drift downstream and develop in brackish or sea water (our sources do not confirm this for this species). It will not overrun a freshwater tank. Raising the young needs a brackish or marine larval set-up and is rarely managed.

Compatibility and tank mates

Peaceful; safe with shrimp, small fish and plants. Avoid loaches, puffers, assassin snails and large crayfish, which eat snails. Its flat shape makes it hard for most fish to attack once it clamps down.

Last updated 8 October 2026. Community-edited care guide on Aquatic-Auctions.