How to breed mystery snails (and stop them)

Mystery snails lay a pink or cream clutch of eggs above the waterline, often overnight. Each clutch can hold a hundred or more babies. Whether you want more snails or none at all, the key is knowing what to do with that clutch.

I've bred mystery snails in my own tanks.

The basics

• You need a male and a female. Unlike many pest snails, mystery snails aren't both sexes in one.
• Telling them apart is hard. When a snail is out of its shell, a male's sex organ can sometimes be seen under the left side of the mantle. Most people buy 4 to 6 and wait.
• Females store sperm, so a lone female can lay fertile clutches for months.
• Warm water speeds it up. They breed most around 76–80°F.

The egg clutch

The female climbs out of the water, usually at night, and lays a clutch on the glass or lid. It starts soft and pink or cream, then hardens and slowly darkens as the babies develop. It hatches in about 2 to 4 weeks, and the babies drop into the water.

• Leave a gap of 1 to 2 inches between the water and the lid, and keep the lid on so the air stays humid.
• Don't let it dry out or get wet. A dry clutch dies, and a clutch under water drowns.
• Moving it: once it has hardened for a day, you can gently pop it off and place it in a small container on a damp paper towel, floating on the tank, until it hatches.

Raising the babies

• Calcium for strong shells: a piece of cuttlebone, calcium-rich food, and water that isn't too soft. See aquarium pH.
• Food: algae wafers, blanched vegetables and shrimp food. Babies are tiny, so crush it.
• Keep fish that eat snails away, like loaches, puffers and large cichlids.

How to stop them breeding

Check the glass above the waterline every few days. Remove any clutch you find and freeze it before throwing it away, so it can't hatch in the trash. Never release snails or eggs into ponds, lakes or streams.

Mystery snails vs other snails

Nerite snails lay small white eggs on hard surfaces, but they can't hatch in fresh water. Ramshorn and bladder snails breed on their own and can quickly fill a tank. See aquarium snail care for all of them.

Related: Aquarium snail care · Cherry shrimp care · Algae types and fixes · Breeding aquarium fish