Ramshorn snail

Overview

Ramshorn snails (Planorbella duryi and relatives) are flat, coiled snails — often red or brown — that arrive in most tanks sooner or later, usually as plant hitchhikers. They’re peaceful, efficient grazers of algae, biofilm and leftovers and generally leave healthy plants alone. Whether they’re welcome cleaners or a nuisance comes down almost entirely to how much you feed. They come in appealing red and blue-brown forms, and some keepers deliberately cultivate a small colony as living clean-up crew and as a supplementary food source for larger fish and assassin snails.

Tank & water

A 19 litre (5 gallon) tank suits them, and they thrive in almost any stable community setup. Like most snails they prefer harder water:

• A cycled tank — cycle fully; they dislike ammonia and nitrite.
• Harder, alkaline water — pH above 7 with some hardness keeps their shells solid.
• Calcium — hardness and minerals prevent thinning, pitted shells.
• No copper — lethal to snails and shrimp; check medication and fertiliser labels.

Feeding

Ramshorns are omnivores that graze algae, biofilm and leftovers, and a normal community tank feeds them without any extra effort. Deliberate feeding is rarely needed; if you do supplement, keep it minimal, because every extra scrap of food fuels faster breeding. If you want them gone rather than merely controlled, the same principle applies in reverse: starve the tank of surplus food and the colony shrinks itself back to a handful of individuals.

Tankmates & breeding

Ramshorns are entirely peaceful and mix with any community fish, shrimp and snails. They breed readily on their own, laying gelatinous egg clutches on glass and plants, so numbers track the food supply. If they get out of hand, an assassin snail will thin them out. Left to a sensibly fed tank, though, their numbers usually settle at a level that quietly matches the available food.

Compare with the burrowing Malaysian trumpet snail and the pest-eating assassin snail.