Siamese Algae Eater (Crossocheilus cf. langei)

Siamese Algae Eater (Crossocheilus cf. langei) is an active Southeast Asian river fish valued for natural grazing behaviour. The cf. is intentional: it means the stock is being compared with Crossocheilus langei rather than claiming a laboratory-confirmed species identity. That is a more accurate way to handle a trade group in which several similar Crossocheilus species are commonly sold under the same English name.

This product has several supplied-size variants. Choose the live Shopify size option when ordering; the selected variant is the authority for supplied size, price and availability. The aquarium should be planned around the adult fish, not the smallest delivery option.

What you are buying

• Trade name: Siamese Algae Eater
• Listing identification: Crossocheilus cf. langei
• Why “cf.” is used: the stock resembles C. langei, but closely related algae-eating Crossocheilus are difficult to distinguish reliably from trade names or photographs alone
• Verified reference for C. langei: FishBase records a maximum of 14.5 cm total length and distribution in Malaysia and Sumatra, Indonesia
• Temperament: active and generally peaceful with appropriately chosen tank mates
• Diet: natural surface grazing supplemented with a complete aquarium diet

Identity matters with Siamese Algae Eaters

“Siamese Algae Eater”, “SAE”, “Flying Fox” and “red-algae eater” are used inconsistently in the aquarium trade. Several Crossocheilus species have similar elongated bodies and dark lateral markings, and common names alone are not enough to establish species identity.

FishBase recognises Crossocheilus langei as a valid species and records it from Malaysia and Sumatra. Because the current stock is sold as Crossocheilus cf. langei, we retain that cautious identification rather than silently changing it to another species for SEO purposes.

Adult size and aquarium length

The verified FishBase record for C. langei reaches about 14.5 cm total length. Similar aquarium-trade Crossocheilus can also become substantial, streamlined adults, so these fish need much more swimming space than their juvenile delivery size suggests.

Our current house planning starts around 200 litres with approximately 120 cm or more of aquarium length, with larger tanks preferable for a proper social group or busy community. A long aquarium is more useful than a tall narrow tank of the same volume.

Flow, oxygen and filtration

Crossocheilus are river-oriented cyprinids. Provide a mature aquarium with strong biological filtration, good circulation and plenty of surface movement. The goal is clean, oxygen-rich water rather than an extreme current that forces the fish to fight the flow continuously.

Smooth stone, wood and robust plants create useful grazing surfaces. Keep open swimming lanes through the aquascape and make sure smaller supplied-size fish cannot be pulled into exposed filter intakes.

Water parameters

Because this listing retains a cautious cf. langei identification, we do not pretend that one narrow laboratory-style parameter range is proven for every fish in the trade group. A stable tropical setup around 23–27°C, near-neutral water and moderate mineral content is a practical house target for healthy acclimated stock.

Ammonia and nitrite should remain at zero. Keep nitrate controlled through sensible stocking, feeding and water changes. Good oxygenation becomes increasingly important as temperature rises.

Feeding and natural grazing

Siamese Algae Eaters spend substantial time browsing rock, wood, leaves and other surfaces. Mature biofilm and soft algal growth are useful parts of the environment, but algae should not be the only food.

Offer quality sinking or midwater pellets, spirulina/algae-based foods, suitable vegetables and small frozen foods for variety. Feed enough to maintain good body condition while still allowing natural grazing behaviour.

Do not deliberately starve the fish to force more algae consumption. A healthy grazer needs a complete diet.

Will it eat black beard algae?

This is one of the most common reasons people search for Siamese Algae Eaters, but it needs a careful answer. Some individuals and some Crossocheilus forms graze nuisance red/brush algae more readily than others. Age, hunger, alternative foods and the exact fish identity all affect what is eaten.

For that reason we do not guarantee black beard algae removal. Good algae control still depends on lighting, nutrient balance, plant health, maintenance and feeding. The fish should be chosen because you can meet its welfare needs even if it never becomes the algae solution you hoped for.

Social behaviour

These are active social fish. Where aquarium size permits, our house guidance favours a group of around five or more rather than an undersized two- or three-fish group that can concentrate social pressure.

If the aquarium cannot comfortably house a proper adult group, plan stocking carefully. Watch for persistent chasing, one fish being excluded from food or repeated hiding behind equipment.

Tank mates

Good companions are active peaceful community fish that share similar water and oxygen requirements. Medium rasboras, barbs, rainbowfish and other robust river-oriented species can work well in a sufficiently large aquarium.

Avoid aggressive cichlids that attack the grazer, very slow delicate long-finned fish in cramped tanks and combinations where the Siamese Algae Eater cannot reach food because of faster dominant tank mates.

Planted aquariums

Siamese Algae Eaters are popular in planted tanks because they spend time browsing hardscape and broad leaves. Mature wood, stone and plant surfaces provide extra grazing area. Leave plenty of open swimming space and protect fragile newly planted stems where necessary.

Secure cover

Active river fish can jump when startled, particularly during introduction or maintenance. Use a secure lid and close gaps around hoses and cables.

Before ordering

Choose a Siamese Algae Eater if you want an active river grazer and you can provide a mature, oxygen-rich aquarium with enough adult swimming space. Reconsider if the aquarium is small, newly cycled, or if the purchase depends entirely on a promise that the fish will remove one particular algae.

Use the live Shopify variant selector for current supplied size, price and stock. The cautious Crossocheilus cf. langei identification is retained deliberately so the product page remains truthful about what is known and what is not.