rm
Passport
- Family
- Flying Fox
- Grows to
- 15 cm (5.9")
- Lives
- 10+ years
- Temperament
- Peaceful
- Care
- Beginner
- Swims
- On the bottom
- Keep
- One is fine
- Water
- 20–26 °C (68–79 °F)
MalaysiaThailandIndonesia
Care requirements
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On record for Siamese Algae Eater: adult size, lifespan, minimum tank, temperature, ph, hardness, minimum group, diet, care level, swim level, tank length.
A figure that is not on record is left out rather than guessed. One marked Suggested comes from keeping knowledge rather than a page.
- Minimum tank 114 L / 30.0 US gal
- pH 6–7.5
- Hardness 1–15 dGH
- Diet algae grazer
- Tank length 150 cm minimum
Care notes written from general aquarium knowledge, not from the cited sources.
About
Siamese algae eaters have a reputation as the one fish that will reliably eat black beard algae, and that reputation is why anyone puts up with the confusion around them.
The confusion is substantial, and it is not settled even among the people who study these fish. Several similar Crossocheilus are traded under the same names, shops rarely know which they have, and the scientific identity of the aquarium “Siamese algae eater” is itself disputed — the stripe usually offered as the test varies between them. What you can lean on is the contrast with a flying fox: no gold band above the black stripe, and plain fins rather than coloured ones with white edges. Past that, treat any confident identification in a shop with suspicion.
They're active, peaceful and long-lived, and they grow larger than most people expect from the small fish in the shop tank.
Tank setup
Give your algae eaters length and open water. They're restless, fast, and they cover the whole tank rather than clinging to one spot.
Cover the tank. They jump, and they're strong enough to find any gap.
Provide flat surfaces to graze: broad leaves, smooth stones, wood, glass. That's where they work.
Give them decent flow. They come from fast Southeast Asian streams and they use a current.
Keep a group or keep one. In between tends to mean one dominant fish harassing the others, though it rarely gets serious.
Feeding
Siamese algae eaters graze algae genuinely and thoroughly when young.
Feed them anyway. Here's the catch nobody mentions in the shop: as they mature they become far more interested in prepared food than in algae, and an adult that has discovered flake often stops grazing altogether.
Keep some vegetable content in the diet — algae wafers, blanched vegetables, spirulina — and don't overfeed the tank, which is what accelerates the switch.
Avoid: buying them as a permanent algae solution. They're a good one for a year or two and an ordinary community fish after that.
Filtration and flow
Good flow and strong oxygenation. They're stream fish and they're happiest in well-circulated water.
Filter properly for an active fish that grows respectably large.
Regular water changes suit them; they're hardy but they're not indifferent.
With plants
Siamese algae eaters are safe with healthy plants and clean algae off leaves that nothing else can reach.
They'll graze soft plants if the tank runs short of algae and they aren't fed, so keep their vegetable food coming.
Broad-leaved plants give them grazing surface and resting places at the same time.
Health
They're hardy and long-lived, and they rarely fall ill.
Jumping is the practical hazard — keep the tank covered.
They're fast and busy enough to unsettle shy fish simply by existing, which is worth noticing before you blame something else for a nervous tank.
Breeding
They're not bred in home aquaria in any practical sense, and commercial stock is produced on farms with hormone induction.
The wild trigger is seasonal, involving changes in flow and water chemistry through a monsoon cycle, and a tank cannot reproduce it.
There are no reliable reports of accidental home spawnings to build on. If you want more, you buy them.
Tank mates
Avoid8
- Common Pleco Common Pleco grows to 45 cm against Siamese Algae Eater at 15 cm, big enough to eat it.
- Common Goldfish Common Goldfish is not safe with Siamese Algae Eater: common goldfish and flying fox are a bad pairing.
- Demasoni Cichlid Demasoni Cichlid is not safe with Siamese Algae Eater: african cichlids and flying fox are a bad pairing.
- Discus Siamese Algae Eater and Discus do not mix: discus and flying fox are a bad pairing.
- Electric Yellow Lab Siamese Algae Eater and Electric Yellow Lab do not mix: african cichlids and flying fox are a bad pairing.
Only with care30
- Chinese Algae Eater Chinese Algae Eater is aggressive and Siamese Algae Eater is peaceful.
- Convict Cichlid Convict Cichlid is aggressive and Siamese Algae Eater is peaceful.
- Jewel Cichlid Jewel Cichlid is aggressive and Siamese Algae Eater is peaceful.
- Amano Shrimp Siamese Algae Eater is a risk to Amano Shrimp: flying fox and shrimp and yabbies are a pairing to watch.
- Bamboo Shrimp Siamese Algae Eater is a risk to Bamboo Shrimp: flying fox and shrimp and yabbies are a pairing to watch.
No conflict is recorded with the other 66 species in the database, so nothing to flag. 4 species are not covered at all, so they could not be judged either way.