Malaysian Trumpet Snail

Species: Melanoides tuberculata.

Size: a cone shell of 2.5–3.8 cm.

Water: 22–30 °C, pH 6.5–7.5.

Eats: biofilm, algae and detritus; does not harm healthy plants.

Breeding: gives birth to live young and breeds readily.

The Malaysian trumpet snail has a long, pointed cone shell in shades of brown, often with darker flecks, and comes from fresh waters across Southeast Asia. It is a burrower. By day it works down into the sand or gravel, and after lights-out it comes up to graze across the substrate (the layer of sand or gravel on the tank floor) and the glass.

That burrowing is the reason people keep it. As it moves through the substrate it loosens the top layer, which helps stop it packing down into pockets where no oxygen reaches and waste rots. It eats biofilm (the thin living film of bacteria and microscopic life that coats every surface), algae and detritus (the fine waste of food and dead leaves that settles on the bottom). Healthy plant leaves are not eaten and roots are not disturbed.

This is a livebearer: rather than laying eggs it releases fully formed baby snails, and it breeds readily. Numbers track how much surplus food reaches the bottom, and because the snails live in the substrate and can survive months in damp gravel, they are very hard to remove once established. It is worth deciding on them deliberately rather than discovering them later.

Water: 22–30 °C and pH 6.5–7.5, with a carbonate hardness (KH, the water's buffer against pH swings) of around 2–12 dKH. Some dissolved calcium keeps the shell from eroding.

Tank: a bed of sand or fine gravel a few centimetres deep gives it room to burrow, and this is where it does its most useful work. Expect to see very few by day.

Feeding: it lives on what settles to the bottom. Offer a blanched vegetable or an algae wafer only if the tank is very clean, and feed the tank lightly overall, since food that reaches the substrate is what drives the population up.