Siamese Algae Eater (Crossocheilus oblongus)

The Siamese Algae Eater (Crossocheilus oblongus) is one of the hardest-working cleanup fish in the freshwater hobby, and one of the very few that will actually eat tough black beard algae. Peaceful, active, and easy to keep, it earns its place in planted community tanks by grazing surfaces clean all day long. This is a beginner-friendly, peaceful schooling fish that does best in a small group. Browse our full selection of freshwater fish and plants.

Care Guide

• Tank size: 30 gallons or larger. These are active, fast swimmers that reach about 6 inches, so they need open room to cruise.
• Keep them in a group: They are social and do best in groups of 4 to 6. Kept singly or in pairs, older fish can get a little nippy with their own kind.
• Water: 75 to 79°F with a pH of 6.5 to 7.5. They are hardy and adapt well to most stable community setups.
• Aquascape: Provide plants, driftwood, and rocks. The biofilm and algae that grow on these surfaces are a natural food source.
• Diet: Omnivore. They graze algae and biofilm but need a varied diet of quality flakes or pellets, plus blanched vegetables, to stay healthy long term.

Specifications

Compatibility

Siamese Algae Eaters are excellent community fish. They mix well with other peaceful species and spend their day busily working over plants and hardscape. Great tank mates include:

• Neon Tetras, Zebra Danios, and other peaceful schooling fish
• Corydoras catfish and Otocinclus for an even stronger cleanup crew
• Nerite snails to round out algae control

Avoid housing them with large or aggressive fish. They can be kept with adult Neocaridina shrimp, though hungry adults may snack on tiny shrimplets, so dedicated shrimp breeders should plan accordingly.

Recommended Foods and Supplies

• Seachem NutriDiet Chlorella Flakes for plant-based nutrition
• Hikari Vibra Bites and Ocean Nutrition Brine Shrimp Plus Flakes for variety
• Live plants such as Anacharis and Hornwort for grazing surfaces and cover
• More freshwater livestock and supplies

FAQ

Do they really eat black beard algae?
Yes. The Siamese Algae Eater is one of the few fish that will eat black beard and hair algae, especially while young and hungry. Feed other foods sparingly so they stay motivated to graze.

How many should I keep?
A group of 4 to 6 is ideal. They are social and stay calmer and more outgoing in a group than they do alone.

Will they bother my other fish?
No. They are peaceful toward other species and simply want open swimming space and surfaces to graze.

How do I tell a true Siamese Algae Eater from a flying fox?
On a true SAE, the black side stripe runs all the way into the tail fin and the fins are clear. Flying foxes and lookalikes have a stripe that stops at the tail base and more colorful fins.