No single fish, shrimp or snail eats every type of algae — pick the wrong one and you get a huge, aggressive bruiser that ignores algae and shreds your fish. This guide covers the 9 species that actually earn a spot on the cleanup crew, matched to the algae they target and the tank size they belong in, plus the one commonly-sold species we tell you to skip entirely.
Reviewed by the AquariumStocking team
Soft green film on glass and leaves is what otos, nerites and amanos eat. Brown diatoms on a new tank vanish under otos and nerites within days. Green spot algae on glass needs a scraper or a nerite. Green hair and thread algae are amano shrimp and bristlenose territory. Black beard algae is not really eaten by anything reliably — it needs CO2, flow and light fixed. Match the crew to the problem instead of hoping.
The single biggest cause of algae-eater deaths is expecting them to survive on tank algae alone. A mature tank produces enough biofilm for a small oto or nerite group, but bristlenose, twig cats, rubber lip plecos and amanos all need supplemental food — sinking algae wafers, blanched cucumber, zucchini and repashy. Feed once a day after lights-out and remove uneaten food within 12 hours.
A common pleco eats algae for the first few months, then stops touching it and produces the bioload of ten neon tetras. Bristlenose stay under 12 cm and are the ONLY plecostomus that belongs in a standard community tank. Everything on this list is bioload-appropriate for the tank size in the min-tank column — don't add a full cleanup crew to a nano and expect it to compensate for skipped water changes.
Nerite snails will lay hard white eggs everywhere but won't reproduce in freshwater — the eggs are cosmetic only. Mystery snails ignore healthy plants but will eat soft new growth if underfed. Amanos won't touch plants but will scavenge shrimp fry. Siamese algae eaters get territorial with age and shouldn't share a tank with slow, long-finned fish. Read each entry below before mixing.
No cleanup crew keeps up with 10-hour light periods, phosphate-rich fish food surplus and inconsistent water changes. Cut the photoperiod to 6–7 hours, reduce feedings, add live fast-growing plants (hornwort, floaters) to outcompete algae, and only then add an algae crew as maintenance rather than a rescue team.
Every parameter below is pulled live from our species database.
Otocinclus vittatus
The best small algae eater in the hobby — 3 cm, peaceful, and specialised for the soft brown/green film that carpets a new planted tank. Needs a mature, cycled tank (6+ weeks), a group of 6+ and gentle flow. Not a rescue crew for a broken tank; add them to a healthy setup and they thrive for years.
Crossocheilus oblongus
One of the few fish that actually eats black beard algae, and reliable on hair and thread algae too. Grows to 14 cm and gets more territorial with age — best kept as a single specimen or a group of 5+ in a 200 L+ tank with active tankmates. Frequently mis-sold as flying fox or Chinese algae eater; check the black stripe runs into the tail.
Ancistrus sp.
The only pleco most keepers should buy. Stays under 12 cm, actively grazes green spot and diatom algae, tolerates community parameters, and breeds easily in a cave setup. One per 100 L / 25 US gallons; supplement with algae wafers, blanched veg and driftwood for rasping.
Panaqolus maccus
A small, striking pleco (10 cm) that lives on driftwood — it needs wood in the tank the way you need water. Cleans up biofilm rather than green algae, so pick it for the personality and community-friendly size, not as a green-algae solution. Great choice for a planted 75 L+ tank with driftwood.
Chaetostoma formosae
An underrated algae workhorse — 18 cm, peaceful, and stays interested in algae into adulthood unlike common plecos. Excellent for cooler community tanks (18–24 °C) with hillstream loaches or coldwater setups. Needs current, oxygenated water and a 150 L+ tank.
Neritina sp.
The best algae snail full stop — clears green spot, film and brown diatom algae, ignores plants, and won't overpopulate in freshwater (eggs are laid but won't hatch). One nerite per 40 L keeps glass and hardscape spotless. Downside: the white eggs stick to everything and are cosmetic-only.
Pomacea bridgesii
A larger, decorative snail (5 cm) that grazes leftover food, biofilm and soft algae rather than aggressive green spot. Best treated as a cleanup-crew scavenger and centrepiece invert, not a green-algae solver. Handles hard, alkaline water and needs calcium for shell health.
Caridina multidentata
The gold standard for hair and thread algae — a group of 6 amanos will strip a hair algae outbreak in a 100 L tank in under a week. Big enough (5 cm) to survive with most community fish, and one of the few shrimp that stays productive at 24 °C+ tropical temps.
Farlowella acus
A stick-thin 15 cm plec relative that grazes green film algae from leaves, wood and glass without disturbing plants. Peaceful and community-safe but sensitive to water quality — needs a mature tank, stable parameters and supplemental veg feeding. Best in soft, planted 100 L+ community tanks.
Gyrinocheilus aymonieri
Frequently sold as a beginner algae eater in the same tanks as siamese algae eaters. Grows to 15 cm+, largely ignores algae as an adult, and turns increasingly aggressive — will latch onto the slime coat of larger flat-bodied fish (goldfish, discus, angels) and cause serious injury. Get a bristlenose or siamese algae eater instead.
Sort by any column — tap a header to reorder.
| Nerite Snail | 5 gallons | 72-79°F | 7–8.5 | 2.5 cm (1") | Beginner | Peaceful |
| Mystery Snail | 5 gallons | 68-82°F | 7–8 | 6 cm (2.4") | Beginner | Peaceful |
| Amano Shrimp | 5 gallons | 68-79°F | 6.5–7.5 | 5 cm (2") | Beginner | Peaceful |
| Otocinclus | 15 gallons | 72-79°F | 6–7.5 | 4 cm (1.6") | Intermediate | Peaceful |
| Clown Pleco | 20 gallons | 75-86°F | 6–7.5 | 9 cm (3.5") | Beginner | Peaceful |
| Siamese Algae Eater | 30 gallons | 75-79°F | 6.5–7.5 | 15 cm (5.9") | Beginner | Peaceful |
| Bristlenose Pleco | 30 gallons | 73-81°F | 6–7.5 | 12 cm (4.7") | Beginner | Peaceful |
| Rubber Lip Pleco | 30 gallons | 70-79°F | 6.5–7.5 | 12 cm (4.7") | Beginner | Peaceful |
| Twig Catfish | 30 gallons | 75-82°F | 6–7.5 | 16 cm (6.3") | Advanced | Peaceful |
| Chinese Algae Eater | 55 gallons | 75-82°F | 6–8 | 25 cm (9.8") | Beginner | Aggressive |
Nerite snails (any tank from 20 L up) and a small group of otocinclus catfish (mature 40 L+ planted) are the best small-tank options. Amano shrimp handle hair algae in tanks from 40 L. Skip any pleco under a 100 L tank — bristlenose need at least that.
Only siamese algae eaters (Crossocheilus oblongus) reliably eat black beard algae, and even they need to be genuinely hungry. Fixing the underlying cause — excess light, low CO2, poor flow, phosphate buildup — is more effective than hoping a fish clears it for you.
One bristlenose per 100 L, one nerite per 40 L, 6+ otos in tanks over 60 L, and 1 amano shrimp per 20 L for hair algae outbreaks. More is not better — an overstocked cleanup crew starves and dies once the algae is gone.
Most algae-eater deaths come from adding them to an immature tank (not enough biofilm), not supplementing food once algae runs out, or copper contamination from medication or tap water. Otos and shrimp are especially sensitive to all three.
No. Chinese algae eaters are sold cheaply as beginner algae eaters but grow to 15 cm, largely stop eating algae as adults, and become aggressive — they will attach to the slime coat of larger flat-bodied fish and injure them. Choose a bristlenose pleco or true siamese algae eater instead.
