| What It Is | Inverts that eat algae & detritus |
| Members | Snails, hermits, crabs, cucumbers |
| Job | Graze algae, stir sand, scavenge food |
| When to Add | After the tank is cycled |
| Golden Rule | Match crew size to the tank, not hype |
Overview
A clean-up crew (CUC) is the team of snails, hermit crabs, and other inverts that graze algae, scavenge uneaten food, and stir the sand — your first line of defense against algae and detritus. They don’t replace nutrient control, but a good crew keeps surfaces clean and the tank looking cared-for.
Who Does What
- Grazing snails (turbo, astrea, trochus) — mow algae off glass and rock; turbos are algae-eating machines.
- Nassarius snails — live in the sand and pop out to scavenge leftover food; great sand-bed cleaners.
- Hermit crabs (blue/red-leg) — scavenge detritus and some algae (give them spare shells).
- Emerald crabs — help with hair and bubble algae.
Sizing & Timing
- Add the crew after the tank is cycled and a little algae has appeared — they need something to eat.
- Start modest and add more if needed; an oversized crew starves once the algae is gone.
- Mix roles — glass grazers, sand sifters, and scavengers — rather than 50 of one snail.
Common Mistakes
Buying a huge “CUC package” on day one: they starve in a clean new tank — add gradually. Expecting them to fix a nutrient problem: they graze symptoms; you still must export nutrients. Forgetting hermit shells: shell-less hermits kill snails for their shells — add empties.
Related Guides
How to Beat Hair Algae (Green Hair Algae) · How to Lower Nitrates and Phosphates · Emerald Crab · Turbo Snail · Nassarius Snail
Frequently Asked Questions
What is a cleanup crew?
A mix of snails, hermit crabs and other inverts that graze algae, sift sand, and eat detritus and leftover food, helping keep the tank clean and nutrients down.
What should be in my cleanup crew?
A variety: algae-grazing snails such as astrea, turbo and cerith; sand-sifters like nassarius and conch; and a few hermit crabs. Diversity covers more jobs than lots of one species. Add it once the tank has some algae to eat.
How many cleanup crew members do I need?
Start modest, around one grazer per few gallons, and add more only if algae outpaces them. Overstocking a new tank cleanup crew just starves them once the algae is gone.