Trochus snail (Tectus fenestratus) care guide

Group
Snails
Other names
Banded trochus snail, Fenestrate top shell, Latticed top shell, Trochus fenestratus, Tectus snail
Family
Tegulidae
Origin
Central and west Pacific, Indo-China and Indo-Malaysia, Papua New Guinea, New Caledonia and northern Australia
Water
saltwater
Maximum size
5 cm
Temperature
22–26°C
pH
8.1–8.4
Hardness
dKH 8–12, SG 1.023–1.025
Minimum tank
40 litres
Care level
beginner
Reef safe
yes

Care

Tectus fenestratus, the fenestrate or latticed top shell, is one of the cone-shaped 'trochus' snails sold as reef clean-up crew. It was originally described as Trochus fenestratus and is now placed in Tectus, family Tegulidae; snails sold as 'trochus' are often not identified to species, so check what you are buying. Its solid, pointed shell is white or grey mottled with green, brown or olive, with a white base, knobs along the sutures and a beaded edge to the base. Shells measure 1.7–5 cm. Trochus snails are among the best general algae grazers for reef tanks. They graze film algae, diatoms and cyanobacteria from rock, glass and sand, and pick at short hair algae, working day and night. They do best in an established tank with plenty of rock to forage on. Typical guidance is one snail per 8–11 litres (about one per two to three US gallons). Unlike turbo snails, trochus can usually right themselves when they fall over. They are sensitive to high nitrate and to copper, and should be drip-acclimatised. In a very clean tank they can starve, so add dried seaweed if algae runs short. Copper-based medicines and some plant fertilisers are toxic to shrimp, snails and most invertebrates. Sources: LiveAquaria (liveaquaria.com/products/banded-trochus-snail); Wikipedia (en.wikipedia.org/wiki/Tectusfenestratus). Checked October 2026.

Diet

A herbivore. Grazes film algae, diatoms, cyanobacteria and soft green algae on rock, glass and substrate; it only nibbles hair algae when it is short. Supplement with dried seaweed (nori) or algae wafers if natural algae runs out.

Breeding

Sexes are separate but look identical. Trochus spawn readily in reef tanks, often triggered by changes in light or water conditions: they release eggs and sperm into the water as a cloudy white puff. The larvae drift briefly before settling on rock, and in a mature tank with few planktivores some survive and grow into adults over a few months.

Compatibility and tank mates

Reef safe: harmless to corals, clams, fish and other invertebrates. Its tall, sturdy shell makes it harder for crabs to eat than many snails, but hermit crabs may still kill it for its shell if they lack spare shells. Avoid triggers, puffers, large wrasses and other snail-eaters.

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

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