Snail (grazer)

Trochus snail

Trochus spp.; Tectus spp.

Group: Snail (grazer)
Care level: Beginner
With corals: Reef safe

What does the trochus snail do in a reef tank?

Film algae, diatoms, cyanobacteria, a wide range of algae on rock and glass

With corals: Yes

How many should you keep?

1 per 50 L (11 US gal); forum rules of thumb range from 1 per 2 to 3 US gal

One US gallon is 3.785 litres and one UK gallon is 4.546 litres, so a "per gallon" rule depends on whose gallon it means.

What can go wrong?

Breeds in some tanks. Can right itself if it falls, unlike Astraea

Photo note: Shell photos, not live animals.

Which tankmates are risky?

Fish

Fish that may eat or harass it.

None of the fish in this guide is known to eat or harass it.

Other invertebrates

Invertebrates it may harm, or that may harm it.

Take care (2)

Blue leg hermit crabBlue leg hermit crabs kill snails to take their shells; give spare empty shells.
Large hermitsLarge hermitss kill snails to take their shells; give spare empty shells.

These checks follow the reasons fish and invertebrates clash: same species or genus, similar shape, mouth size, temperament, food, burrows, tank size and the order they are added. Individual animals differ; every source agrees on that.

Where sources disagree

Where sources disagree
Topic	What sources say	Our reading
How many to keep	1 per 50 L (11 US gal); forum rules of thumb range from 1 per 2 to 3 US gal	Per-gallon rules ignore how much food the tank grows. Start low, add more only when algae or leftovers build up, and convert US gallons at 3.785 litres.