Famous for being one of the few freshwater fish that actively consumes Black Beard Algae (BBA). A torpedo-shaped, active bottom-to-midwater swimmer native to Southeast Asian streams. True Siamese Algae Eaters feature a distinct black horizontal stripe that extends all the way through the tail fin. As they mature, they can become lazy, preferring prepared foods over algae, and may occasionally chase other bottom dwellers.
At a Glance
Tank Requirements
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Water Parameters
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Temperament & Compatibility
Available Varieties
Each variety inherits the species defaults above. Only differences are highlighted.
Standard
The standard true Siamese Algae Eater. Excellent algae grazers when young. Provide a tight-fitting lid as they are easily spooked and prone to jumping.
Differs in 1 trait from base species
Also known as: True Siamese Algae Eater, Juvenile SAE
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🟢Ideal Tank MatesSiamese Algae Eater Care Guide Summary
The Siamese Algae Eater, scientifically known as Crossocheilus oblongus, belongs to the Cyprinids family group. Adults reach a maximum size of approximately 15 cm and have a fusiform body shape with a moderate growth rate. Classified as mostly peaceful, this species primarily occupies the bottom and mid-level zones of the aquarium and produces a medium level of biological waste.
To thrive, the Siamese Algae Eater requires a freshwater only aquarium with a minimum volume of 110 litres and a tank length of at least 90 cm. Water temperature should be maintained between 22°C and 28°C, with a pH range of 6–7.5 and a general hardness of 5–15 dGH. A moderate water flow is preferred. An aquarium test kit can help you monitor these values.
Due to its specialist needs, the Siamese Algae Eater is best suited for fishkeepers who can provide a carefully planned setup. The Siamese Algae Eater is typically available in one standard form.
Siamese Algae Eater Habitat Setup
When setting up an aquarium for the Siamese Algae Eater, a moderate water flow best suits their natural preferences. Because this species occupies the bottom and mid-level zones, the aquarium layout should prioritise open swimming space in the centre of the tank for free movement and sufficient floor space with hiding spots among rocks, wood, or dense planting. Useful additions include driftwood, which can serve as both a hiding place and a dietary supplement, an established tank with natural algae growth, as they depend on it as a primary food source, and light plant coverage for partial shade. Keepers should note that a tight-fitting lid is essential, as this species is a known jumper.
Siamese Algae Eater Compatibility Notes
Classified as mostly peaceful, the Siamese Algae Eater is adaptable and can be kept singly or in a small group, offering flexibility when planning a community tank. When choosing tankmates, territorial behaviour may cause issues if hiding spots or floor space are limited, shy or slow-feeding tankmates may be outcompeted at feeding time, and their energetic swimming style may stress more sedentary or timid species. Selecting tankmates that favour different water layers from the bottom and mid-level zones can help reduce competition and territorial overlap.
Recommended Tank Sizes
Standard aquarium sizes that meet the minimum volume and length requirements for Siamese Algae Eater.
30 Gallon Breeder
40 Gallon Breeder
55 Gallon Standard
60 Gallon Breeder
75 Gallon Standard
90 Gallon Standard
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Frequently Asked Questions About Siamese Algae Eater
How big does Siamese Algae Eater get?
Siamese Algae Eater (Crossocheilus oblongus) typically reaches a maximum adult size of approximately 15 cm. They have a fusiform body shape and a moderate growth rate.
What tank size does Siamese Algae Eater need?
A minimum aquarium volume of 110 litres and a tank length of at least 90 cm are recommended for Siamese Algae Eater. This ensures enough swimming space and helps maintain stable water conditions.
What water parameters does Siamese Algae Eater need?
Siamese Algae Eater thrives in freshwater only conditions with a temperature range of 22–28°C, a pH between 6 and 7.5, and a general hardness of 5–15 dGH. A moderate water flow is preferred.
Is Siamese Algae Eater peaceful or aggressive?
Siamese Algae Eater is classified as mostly peaceful with an aggression score of 3 out of 10. They are generally well-suited to peaceful community tanks.
Can Siamese Algae Eater live alone?
Yes, Siamese Algae Eater can be kept singly or in a group. They are flexible and adapt well to both setups.
Does Siamese Algae Eater have any special tank requirements?
Yes. Siamese Algae Eater benefits from established algae (otocinclus), driftwood (digestion/hiding), and plants - lighly covered in the aquarium. These features help replicate their natural habitat and promote overall health and well-being.
Does Siamese Algae Eater need a lid on the tank?
Yes. Siamese Algae Eater is a known jumper, and a tight-fitting lid or cover is essential to prevent escape. Even a small gap can be enough for a determined fish to leap out.
Similar Species
Chinese Algae Eater (CAE)
Gyrinocheilus aymonieri
Sold widely as a small, peaceful algae-eating juvenile, the Chinese Algae Eater (CAE) undergoes a drastic behavioral and dietary shift as it matures. Growing up to 25cm (10 inches), adults stop eating algae, become highly territorial, and are notorious for attacking slow-moving, flat-sided fish (like Angelfish, Discus, and Goldfish) to feed on their nutrient-rich slime coat. Best kept in fast-flowing river setups with robust, fast-moving tank mates.
Betta (Siamese Fighting Fish)
Betta splendens
The Siamese Fighting Fish is an aquarium icon known for its labyrinth organ (allowing air breathing) and vivid colors. While hardy, they require heated, filtered water (24-30°C). Males are solitary and fiercely territorial. Females are generally less ornate but can be kept in 'sororities' with strict precautions (minimum 5 females in 75L+).
Harlequin Rasbora
Trigonostigma heteromorpha
A highly popular, peaceful schooling fish recognizable by its metallic copper/orange body and the distinct black triangular 'porkchop' patch on its hindquarters. Originating from peat swamps and blackwater streams in Southeast Asia, they are active swimmers that thrive in heavily planted aquariums with gentle to moderate water flow.
Pictus Catfish
Pimelodus pictus
An extremely active, striking silver catfish with black spots and incredibly long barbels, native to South America. While peaceful toward similarly sized tank mates, they are highly effective nocturnal predators that will easily swallow small fish (like Neon Tetras) whole. They are scaleless and possess sharp pectoral spines that can easily become entangled in aquarium nets.
Bristlenose Pleco
Ancistrus cirrhosus
A highly popular, hardy, and relatively small suckermouth catfish. Excellent algae eaters that stay much smaller than Common Plecos, making them suitable for standard aquariums. They require dietary wood (driftwood) to aid in digestion and plenty of hiding caves.
Glass Catfish
Kryptopterus vitreolus
A highly unique, completely transparent catfish from Thailand. Unlike most catfish, they are mid-water swimmers that require being kept in schools to feel secure. They are incredibly peaceful and easily outcompeted for food. They require stable water parameters and dim lighting or shaded areas provided by floating plants.