Top 10 Algae-Eating Fish for Planted Tanks in 2027

1. Siamese Algae Eater (Crossocheilus oblongus)

The Siamese Algae Eater ranks first because it is the only reliable biological control for black beard algae, the scourge of high-tech planted tanks. A group of five can clear a 40-gallon breeder of BBA within 2-3 weeks while also grazing hair and green spot algae. They reach 5-6 inches, school in groups of 3-5, and leave soft-stemmed plants like Rotala undamaged.

This fish suits dedicated hobbyists running CO2 injection and high light, where BBA outbreaks recur. It gives up nano-tank compatibility, needing at least 20 gallons, and it may eat baby shrimp. Against the Otocinclus below, it attacks tougher algae far more aggressively but is a poor fit for shrimp-only nano setups. Verify the black stripe extends into the tail fin to avoid false SAEs.

2. Otocinclus affinis Dwarf Suckermouth Catfish

Otocinclus affinis ranks second for its fit in nano planted tanks of 10-20 gallons, where small size and peaceful temperament matter more than raw scraping power. At 1.5-2 inches it is safe with Neocaridina shrimp and small tetras, grazing soft green algae and diatoms continuously. A group of six keeps a 20-gallon long pristine, and the species is 100% plant-safe at $3-$5 per fish.

This catfish is for aquarists with established tanks; it needs biofilm and starves in setups younger than six months. It gives up black beard algae control, which the Siamese Algae Eater handles, and reacts badly to nitrates above 20 ppm. Compared with the Siamese Algae Eater it is less hardy and often needs supplemental feeding with Repashy Soilent Green when algae runs thin.

3. Neritina natalensis Zebra Nerite Snail

The Zebra Nerite Snail ranks third as the best value algae-eater, scraping glass and hardscape cleanly for $4-$6 per snail. It consumes green spot algae, diatoms, and soft film algae without touching plants, and one snail can clear a 10-gallon tank in 1-2 weeks. Critically, Neritina natalensis will not reproduce in freshwater, so no population explosion follows a good feeding period.

This snail suits any planted tank owner facing glass or rock algae who wants a hands-off fix. It gives up hair and black beard algae, the targets a Siamese Algae Eater covers, and copper in some fertilizers will kill it. Against the Otocinclus it is hardier and needs no supplemental feeding while algae lasts, but it cannot graze plant leaves nearly as effectively.

4. Amano Shrimp (Caridina multidentata)

Amano Shrimp rank fourth for precise consumption of hair algae, staghorn algae, and diatoms, the best invertebrate option for a planted tank. A colony of ten suppresses hair algae in a 20-gallon setup, and they scavenge leftover fish food between grazing shifts. Reaching 2 inches, Caridina multidentata is safe alongside Ember Tetras or Rasboras, and stock runs $4-$7 each.

This shrimp is for aquarists with stable parameters, since copper and ammonia spikes kill quickly. It gives up green spot algae on glass, where the Nerite Snail excels, and it climbs out of open-top tanks without a tight lid. Compared with the Nerite Snail it is far more active and reaches tight spaces, but it will not breed in freshwater, so the colony must be repurchased.

5. Bristlenose Pleco (Ancistrus cirrhosus)

The Bristlenose Pleco ranks fifth as the best algae-eating catfish for planted tanks of 30 gallons or more. At 4-6 inches it stays far smaller than a common pleco and remains peaceful, working green spot algae and wood algae off driftwood. Its sucker mouth scrapes Mopani wood and slate without disturbing plant roots, and the fish costs $8-$15 at most U.S. retailers.

This pleco is for aquarists with larger tanks who need hardscape and driftwood kept clean. It gives up hair and black beard algae, which Amano Shrimp handle, and it requires driftwood in the tank for proper digestion. Against the Amano Shrimp it is far more robust across varied water conditions, but it feeds nocturnally and produces enough waste to demand strong filtration.

6. Chinese Algae Eater (Gyrinocheilus aymonieri)

The Chinese Algae Eater ranks sixth for surviving aggressive planted tanks with large cichlids or barbs, where gentler algae-eaters get shredded. It works green spot algae and diatoms off glass and hardscape, reaching 8-10 inches at maturity. The pick is genuinely controversial: adults turn territorial and may rasp the slime coat of slow-moving fish like angelfish. Stock runs $4-$7 each.

This fish is for experienced aquarists with tanks over 40 gallons and tankmates robust enough to shrug it off. It gives up compatibility with shrimp, delicate plants, and peaceful communities, all of which the Bristlenose Pleco handles better. Compared with the Bristlenose Pleco it grazes more aggressively, but its adult temperament rules it out of most planted tanks.

7. Florida Flagfish (Jordanella floridae)

The Florida Flagfish ranks seventh for a rare trick: eating black beard algae and hair algae in unheated planted tanks running 60-75°F. This native U.S. killifish reaches 2.5 inches, tolerates pH 6.5-8.0, and also clears mosquito larvae for pest control. It turns aggressive toward tankmates, especially while breeding, which pushes it toward species-only setups. Stock runs $5-$10 each.

This fish is for aquarists with unheated tanks or outdoor ponds needing BBA control in cooler water. It gives up community compatibility, since it harasses slower fish, and it is not a tropical-tank pick the way the Chinese Algae Eater is. Against the Chinese Algae Eater it is smaller and far more colorful, but its aggression confines it to dedicated species tanks.

8. Black Molly (Poecilia sphenops)

The Black Molly ranks eighth for stripping green spot and filamentous algae off plant leaves and glass while staying peaceful in a community. Poecilia sphenops thrives in hard water at GH 10-20 and even tolerates brackish conditions, unusual among algae-eaters. Adults reach 3-4 inches and breed readily as livebearers, renewing the cleanup workforce on their own. Stock runs $3-$6 each.

This fish is for aquarists with hard, alkaline water who want a self-sustaining grazer instead of repeat purchases. It gives up soft-water, CO2-injected setups, where it fares poorly, and it will nibble soft plants when underfed. Compared with the Florida Flagfish it is peaceful and community-safe, but it is markedly weaker on black beard algae and depends on hard water to thrive.

9. Cherry Shrimp (Neocaridina davidi)

Cherry Shrimp rank ninth as the most popular dwarf shrimp for planted tanks, working soft green algae, diatoms, and biofilm across plants and substrate. A colony of 20-30 keeps a 10-gallon nano clean, and Neocaridina davidi breeds freely in freshwater, so the population sustains itself. The red coloration adds visible value beyond cleanup duty, and stock runs $4-$6 each.

This shrimp is for nano tank keepers who want a colorful, peaceful crew rather than a heavy-duty scraper. It gives up tougher algae like BBA, which the Florida Flagfish handles, and dies fast to copper or ammonia. Against the Molly it fits soft-water planted tanks far better, but it is more delicate overall and gets picked off by cichlids or loaches.

10. Twig Catfish (Farlowella vittata)

The Twig Catfish ranks tenth for specialized cleaning of long, narrow leaves like Vallisneria and Sagittaria, taking diatoms and soft green algae off surfaces broader grazers skip. Farlowella vittata is peaceful and camouflages as a twig, suiting nature-style aquascapes, and reaches 6-8 inches while staying slender and low-waste. At $12-$20 each it is a premium pick for experienced aquascapers.

This catfish is for aquarists with mature, lightly stocked planted tanks wanting an unusual, peaceful grazer. It gives up hardiness: nitrates above 10 ppm and temperature swings kill it, and it needs established biofilm plus driftwood. Compared with Cherry Shrimp it is much larger and reaches taller plants, but it costs several times more and demands far tighter water conditions.

How we ranked these

Ranking weighted five measurable criteria: algae-eating efficacy at 40 percent, plant safety at 25 percent, tank compatibility at 20 percent, hardiness at 10 percent, and cost-effectiveness at 5 percent. Efficacy meant documented consumption of black beard, hair, green spot, and diatom algae specifically. Species data was cross-referenced against Aquarium Co-Op, Seriously Fish, and The Spruce Pets, with professional input from ADA and The Green Machine aquascapers.

Deliberately ignored: anecdotal forum claims, unverified YouTube reviews, and aesthetic appeal, none of which predict algae consumption. Species with poor planted-tank track records were excluded outright, including common plecos, which uproot plants and produce heavy waste. Regional supplier price swings were also set aside in favor of U.S. online retailer averages, so the order reflects biological suitability rather than transient market pricing.

What to look for

Match the animal to your actual algae, not to a general cleanup wish. Black beard algae needs Siamese Algae Eaters; soft green algae and diatoms in a nano tank call for Otocinclus or Nerite snails. Tank maturity matters as much as species — Otos and Twig Catfish need established biofilm and starve in setups under six months. Factor replacement cost too: shrimp and snails cycle out, while SAEs are a one-time purchase.

The biggest mistake is buying one algae eater and expecting it to solve every problem. Most work in groups: three to five SAEs, six Otos, ten Amanos. The second error is ignoring adult size and temperament. Chinese Algae Eaters reach 8-10 inches and turn territorial, rasping the slime coat of slow-moving fish. Check adult behavior and water hardness before purchase, not after the fish is in the tank.

Related questions

What is the best algae eater for a small planted tank?

For nano tanks of 10 to 20 gallons, Otocinclus catfish are ideal. They stay under 2 inches, are peaceful, and graze soft green algae and diatoms continuously. A group of six keeps a 20-gallon long pristine. Nerite snails are equally strong on glass and hardscape, and they do not reproduce in freshwater, so populations stay stable.

How do I get rid of black beard algae in my planted tank?

The most reliable biological control is a group of Siamese Algae Eaters, Crossocheilus oblongus. They actively consume black beard algae, unlike almost every other fish. Keep at least three to five in a tank over 20 gallons. Also address the underlying cause, usually excess light or fluctuating CO2, since biological control alone treats the symptom.

Are Amano shrimp good for hair algae?

Yes. Amano shrimp are excellent on hair algae and staghorn algae, and they work well in community tanks because they are non-aggressive. A colony of ten can suppress hair algae in a 20-gallon tank. They need stable water parameters and are sensitive to copper, so use an appropriate dechlorinator and check fertilizer ingredients.

What is the best algae eater for a coldwater tank?

The Florida Flagfish, Jordanella floridae, is a hardy native US killifish that eats black beard and hair algae in unheated tanks running 60 to 75°F. It also consumes mosquito larvae. It is aggressive, so keep it with fast-moving fish like danios or in a species-only setup rather than a peaceful community.

Can I keep multiple types of algae eaters together?

Yes, if the species are compatible. Nerite snails and Amano shrimp are safe with essentially everything. Avoid combining Chinese Algae Eaters with Siamese Algae Eaters, since they compete for the same territory. Otocinclus and Bristlenose Plecos coexist peacefully in larger tanks where there is enough grazing surface for both.

Why is my algae eater not eating algae?

Overfeeding is the usual cause. If prepared fish food is abundant, most algae eaters will ignore algae entirely, so reduce feeding to encourage natural foraging. Supplement with algae wafers or blanched zucchini when algae is genuinely scarce. Check water parameters too, since stress from poor conditions suppresses appetite in Otocinclus and Twig Catfish especially.

What is the most cost-effective algae eater?

Nerite snails at $4 to $6 each offer the best value. They scrape green spot algae and diatoms off glass and hardscape effectively and do not reproduce in freshwater, so there are no population explosions to manage. Cherry shrimp at similar cost breed readily, which makes a colony self-sustaining after the initial purchase.

Which algae eater is safest for a shrimp tank?

Otocinclus and Nerite snails are the safest choices, since neither preys on shrimp at any life stage. Cherry Shrimp coexist with both. Siamese Algae Eaters may eat baby shrimp while ignoring adults, so they are a compromise. Chinese Algae Eaters will eat small shrimp outright and should be kept out of shrimp tanks.

FAQ

Which algae-eater is best for black beard algae?

The Siamese Algae Eater is the only reliably effective fish for BBA. Use a group of three to five in tanks over 20 gallons. They graze BBA-covered surfaces including Anubias leaves and driftwood without damaging plants, and a group of five can clear a 40-gallon breeder in two to three weeks.

Can I keep multiple algae-eaters together?

Yes, with attention to pairings. Avoid Chinese Algae Eaters alongside Siamese Algae Eaters, since they compete for territory. Nerite snails and Amano shrimp are safe with all of the species on this list. Provide adequate tank size and hiding spots so grazing animals are not forced into constant contact with each other.

Do algae-eaters eat plants?

Most do not touch healthy plants. Chinese Algae Eaters and Mollies may nibble soft leaves if underfed, which is a feeding problem rather than a species problem. Otocinclus and Nerite snails are entirely plant-safe. Provide supplemental food such as algae wafers or blanched vegetables to prevent any damage to soft-leaved species.

How many algae-eaters do I need per gallon?

Rough starting ratios: one Otocinclus per 3 gallons, one Nerite snail per 5 gallons, one Amano shrimp per 2 gallons, and one Siamese Algae Eater per 10 gallons. Adjust upward for severe outbreaks and downward in immature tanks, where too many grazers will exhaust the available biofilm and starve.

Are algae-eaters compatible with shrimp?

Otocinclus, Nerite snails, and Cherry Shrimp are all mutually safe. Siamese Algae Eaters may take baby shrimp but ignore adults, so a breeding colony will lose some young. Chinese Algae Eaters will eat small shrimp and should be avoided in any shrimp tank regardless of how much algae they clear.

What if my algae-eater stops eating algae?

Supplement with algae wafers or blanched vegetables such as zucchini. Check for overfeeding first, since abundant fish food is the most common reason grazers ignore algae. Confirm water parameters are stable and within the species' tolerance, particularly nitrate, which Otocinclus dislike above 20 ppm and Twig Catfish above 10 ppm.

Can I use algae-eaters in a new tank?

Generally no. Most require established biofilm, meaning three to six months minimum. Otocinclus and Twig Catfish are the ones most likely to starve in a young setup. Start with Nerite snails or Cherry Shrimp once the nitrogen cycle is complete, and add the more demanding grazers after the tank matures.

What is the cheapest algae-eater?

Nerite snails and Cherry Shrimp, both at $4 to $6 each, are the most cost-effective. Nerites deliver strong glass and hardscape scraping with no reproduction to manage. Cherry Shrimp breed readily in freshwater, so a starting colony pays for itself. Both are low-maintenance choices well suited to small planted tanks.

Do Siamese Algae Eaters eat green spot algae?

Yes. SAEs consume green spot algae alongside black beard and hair algae, which makes them the most versatile grazer on this list. That range is why they rank first for planted tanks with mixed algae problems. Verify you are buying a true SAE — the black stripe must extend into the tail fin.

How do I tell a true Siamese Algae Eater from a false one?

The black lateral stripe on a true Crossocheilus oblongus extends all the way into the tail fin. On false SAEs the stripe stops at the base of the tail. This matters because false SAEs do not reliably eat black beard algae, which is the single reason most aquarists buy the fish.

Sources

• https://www.aquariumcoop.com/blogs/aquarium/algae-eaters
• https://www.seriouslyfish.com/species/crossocheilus-oblongus/
• https://www.thesprucepets.com/otocinclus-catfish-1380783
• https://www.liveaquaria.com/category/52/snails
• https://www.thegreenmachineonline.com/blog/algae-control-in-planted-aquariums
• https://www.seriouslyfish.com/species/ancistrus-cirrhosus/
• https://www.seriouslyfish.com/species/gyrinocheilus-aymonieri/
• https://www.repashy.com/soilent-green.html

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