← All groups · Invertebrates & cleanup crew
The cleanup crew that earns its keep
Snails & Crabs
Snails and crabs are the tank's working cleanup crew — grazing algae, turning sand and scavenging leftovers. The honest rule most guides get wrong: bigger is not better. Overstock a crew and it starves; size it to the tank, and give hermits spare shells so they don't kill snails for one.
12 in our library · 12 with a full care guide.
💧 The one thing to get right: Right-size the crew (overstocking = starvation), give hermits spare shells, and keep the tank copper-free.
- Blue-Leg Hermit Crab Clibanarius tricolor Beginner ✓ Care guide The reef's tiny janitor — grazes hair algae and detritus all day; just give it spare shells.
- Trochus Snail Trochus spp. Beginner ✓ Care guide A workhorse algae-grazing snail that can flip itself back over — the reliable cleanup pick.
- Astrea Snail Astraea tecta Beginner ✓ Care guide A tireless film-algae grazer — the catch is it can't reliably flip itself back over.
- Cerith Snail Cerithium spp. Beginner ✓ Care guide The all-rounder cleanup snail — grazes algae on glass and rock, then burrows and stirs the sand.
- Emerald Crab Mithraculus sculptus Beginner ✓ Care guide The go-to fix for bubble algae — a hardy little crab that eats what snails won't.
- Fighting Conch Strombus alatus Beginner ✓ Care guide The sand-bed cleaner that isn't a fighter — it plows the substrate for detritus and algae.
- Nassarius Snail Nassarius spp. Beginner ✓ Care guide The sand-sifter — buries itself, then erupts to devour leftover food and detritus.
- Nerite Snail Nerita spp. Beginner ✓ Care guide The glass specialist — small and reef-safe, it scrapes film algae and diatoms off the panes.
- Scarlet Hermit Crab Paguristes cadenati Beginner ✓ Care guide The red-legged hermit that truly eats algae — and bothers snails far less than most.
- Serpent Star Ophioderma spp. Beginner ✓ Care guide The rock-dwelling detritus vacuum — a tough, hidden scavenger (just not the green one).
- Turbo Snail Turbo fluctuosa Beginner ✓ Care guide The big, hungry hair-algae eater — mows a bloom fast, but bulky enough to bump loose frags.
- Tuxedo Urchin Mespilia globulus Beginner ✓ Care guide The reef's neat little algae-grazing urchin — great on hair algae, and it decorates itself.
Plan a snails & crabs tank
Our free tools run on these species' real, sourced care data — no guessing:
Cleanup-crew calculator →Parameter targets →Tank volume calculator →Salinity ⇄ SG converter →