The Cleanup Crew Concept
A cleanup crew is a deliberate selection of organisms that consume algae, detritus, and uneaten food — reducing the organic load on your filter and keeping surfaces cleaner between manual maintenance sessions. The key word is "reduce" — no cleanup crew eliminates algae entirely or replaces water changes and glass scraping. They're assistants in your maintenance routine, not substitutes for it.
Effective cleanup crews combine species that target different food sources and occupy different zones. Nerite snails clean glass and hard surfaces. Amano shrimp consume hair algae and detritus on plants and substrate. Otocinclus graze diatom and soft green algae from leaves and glass. Together, they cover more ground than any single species and keep the tank visibly cleaner between your manual maintenance sessions.
Best Snails
Nerite Snails
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The most effective algae-eating snail in the hobby. Consumes green spot algae, diatoms, and biofilm from glass, rocks, and driftwood. Does not reproduce in freshwater. Various shell patterns available — zebra, tiger, olive, and horned varieties.
Mystery Snails
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Large, colorful snails (gold, blue, ivory, purple) that eat algae and detritus. They reproduce in freshwater but lay visible egg clutches above the waterline that can be removed to control population. Fascinating to watch — they extend a siphon to breathe and cruise the glass actively.
Best Shrimp
Amano Shrimp
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The top freshwater algae-eating shrimp. Aggressive consumers of hair algae, soft green algae, and detritus. Need groups of 5+ to make a visible impact. Don't reproduce in freshwater — larvae need brackish water.
Cherry Shrimp
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Red cherry shrimp breed readily in freshwater, establishing self-sustaining colonies. They eat biofilm, detritus, and soft algae. Less effective against tough algae than amano shrimp, but the breeding colony provides continuous replacement without purchasing new shrimp.
Best Algae-Eating Fish
Otocinclus
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Tiny catfish (1.5 inches) that specialize in soft brown diatom algae — the dusty film common in newly established tanks. Need groups of 6+ for comfort and are sensitive to poor water quality. Not effective against green spot or hair algae.
Siamese Algae Eater (True SAE)
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One of the few fish that consistently eats black beard algae (BBA). Grows to 6 inches, so needs 30+ gallons. Active swimmer that covers a lot of ground. Verify you're getting the true SAE, not the similar-looking but less effective flying fox.
Building Your Crew by Tank Size
For a 10-gallon: 2 nerite snails and 3–5 cherry shrimp. For 20 gallons: 3 nerite snails, 5 amano shrimp, and optionally 6 otocinclus. For 40+ gallons: 4–5 nerites, 8–10 amano shrimp, 6–8 otocinclus, and optionally a bristlenose pleco. These combinations cover glass, plants, substrate, and hardscape without overloading the bioload. Remember that cleanup crew members produce waste too — factor them into your stocking calculations.
Managing Pest Snail Populations
Bladder snails, pond snails, and Malaysian trumpet snails arrive uninvited on plants and multiply rapidly in overfed tanks. They're not harmful — they eat algae, detritus, and uneaten food, and they indicate overfeeding more than they cause problems. But their populations can explode to hundreds in a few weeks if food supply supports it.
The most effective population control is reducing food supply: feed fish less, remove uneaten food promptly, and vacuum the substrate regularly. Pest snail populations self-regulate when food is limited — they can't reproduce faster than their food supply supports. Chemical snail removal (copper-based treatments) kills all invertebrates, including beneficial snails and shrimp, and is almost never the right approach.
Assassin snails are a biological control option — they're predatory snails that hunt and consume pest snails. Three to five assassin snails in a 20-gallon tank will steadily reduce a pest snail population over several weeks. They reproduce slowly (unlike their prey), so they don't create a new overpopulation problem. Once the pest snails are controlled, assassins switch to scavenging and supplemental feeding.
Manual removal — picking snails off the glass during weekly maintenance or using a lettuce trap (place a blanched lettuce leaf on the substrate overnight, remove it in the morning covered in snails) — reduces populations quickly. Combined with reduced feeding, manual removal can bring an exploding population under control within a few weeks without chemicals or predatory species.
Shrimp-Safe Practices
If your cleanup crew includes shrimp, avoid copper-based medications in the tank — copper is lethal to all invertebrates at concentrations that are therapeutic for fish. Read medication labels carefully; many ich treatments contain copper or malachite green at levels that kill shrimp. If you need to medicate fish in a tank with shrimp, remove the shrimp to a temporary container (a large jar with an airstone works) until the medication is removed with carbon and water changes.
Fertilizers containing copper at trace levels (present in most planted tank fertilizers) are safe for shrimp in the concentrations recommended for aquarium use. The copper levels in fertilizers are orders of magnitude below the lethal threshold for shrimp.
Stocking for Different Algae Problems
Green spot algae on glass: nerite snails are the only common cleanup crew member that consistently eats it. Amano shrimp and otocinclus ignore green spot algae. Multiple nerites on the viewing panes will keep them clean between manual scraping sessions, extending the interval between glass cleanings from weekly to biweekly or monthly.
Hair algae (long green strands on plants and hardscape): amano shrimp are the most effective consumers. A group of 8–10 amano shrimp in a 20-gallon tank can eliminate a moderate hair algae outbreak within a week. Supplementing with Siamese algae eaters in larger tanks (30+ gallons) provides additional hair algae control that shrimp alone may not fully handle in severe cases.
Brown diatom film (the dusty coating on every surface in new tanks): otocinclus are specialized diatom consumers. A group of 6–8 in a 20-gallon tank clears diatom buildup rapidly. Diatoms are typically a temporary problem in newly established tanks that resolves within 2–3 months as silicate levels in the water column are consumed. Otocinclus handle the transition period, after which they switch to grazing soft green algae and biofilm.
Blue-green algae (cyanobacteria): no common cleanup crew member consumes it reliably. Nerites, shrimp, and otocinclus all avoid cyanobacteria. Treatment requires addressing the root cause — usually low flow, excess nutrients, and insufficient plant competition — through blackouts, erythromycin, or improved circulation rather than biological control.
However, some keepers of sensitive Caridina shrimp prefer copper-free fertilizers (like the Shrimp-Safe formulation from NilocG Thrive) for peace of mind. a targeted crew of appropriate size outperforms a random assortment.Malaysian trumpet snails are worth special mention as a substrate maintenance organism. These small burrowing snails constantly churn through sand and fine gravel substrates, preventing the anaerobic pockets that produce toxic hydrogen sulfide gas. They reproduce prolifically in well-fed tanks, which some keepers view as a drawback, but their substrate aeration service is genuinely valuable in planted tanks and sand-bottom setups where debris settles between the grains and creates dead zones.
Population control for Malaysian trumpets follows the same principle as all pest snails: reduce food input and the population self-regulates within weeks. They cannot reproduce faster than their food supply supports. A stable population in a properly fed tank provides continuous substrate maintenance with no effort from the keeper, making them one of the most practically useful invertebrates in freshwater aquariums despite their modest appearance.
Frequently Asked Questions
What's the best algae eater for a small tank?
Nerite snails and amano shrimp are the most effective cleanup crew for tanks under 20 gallons. Otocinclus work too but need groups of 6+ and can be sensitive to water quality. Avoid common plecos — they grow to 12+ inches and are completely inappropriate for small tanks.
Do cleanup crews eliminate the need for manual cleaning?
No. They reduce algae accumulation but can't eliminate it. You'll still need to scrape viewing panes and vacuum substrate. Think of cleanup crews as maintenance assistants, not replacements — they handle the background algae that makes manual cleaning less frequent.
Will snails overrun my tank?
Nerite snails don't reproduce in freshwater — they lay eggs (small white dots on hardscape) but the larvae need brackish water to develop. Mystery snails reproduce slowly and controllably. Pest snails (bladder snails, pond snails) can overrun a tank if overfed — control them by reducing feeding rather than adding chemicals.