Black shark - Labeo chrysophekadion

Scientific name: Labeo chrysophekadion

Common name: Black shark

Family: Cyprinidae

Usual size in fish tanks: 65 - 90 cm (25.59 - 35.43 inch)

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Recommended pH range: 6.4 - 7.6

Recommended water hardness: 9 - 18°N (160.71 - 321.43ppm)

0°C 32°F30°C 86°F

Recommended temperature range: 23 - 27 °C (73.4 - 80.6°F)

The way how these fish reproduce: Spawning

Where the species comes from: Southeast Asia

Temperament to its own species: aggressive/territorial

Temperament toward other fish species: aggressive to smaller

Usual place in the tank: Bottom levels

Short description

The Black shark (Labeo chrysophekadion), also known as the Black shark minnow or Black labeo, is a massive cyprinid native to Southeast Asia. It is one of the largest species kept in the aquarium hobby, reaching 65–90 cm in length. Juveniles may look manageable, but adults require aquaria of several thousand liters. In captivity they are notorious for becoming extremely territorial and aggressive as they mature. Because of their size and behavior, they are suited only for very large public aquaria or the largest private installations.

Origin

Native to Southeast Asia, particularly the Mekong and Chao Phraya river basins, as well as rivers in Malaysia, Sumatra, and Borneo. They inhabit large rivers and floodplains with strong seasonal flow, and migrate during spawning.

Food and feeding

An omnivore. In the wild it grazes on algae, periphyton, plant matter, and small invertebrates. In aquaria it accepts sinking algae wafers, high-quality pellets, spirulina-based foods, and blanched vegetables (zucchini, peas, spinach). Supplement with live or frozen protein foods such as bloodworms, mysis, and shrimp, though the bulk of the diet should remain vegetable-based to prevent digestive issues.

Sexing

There are no reliable external differences; males and females appear similar. During spawning season, females may appear fuller-bodied.

Breeding

Breeding in home aquaria is virtually impossible due to the species’ large adult size and migratory spawning habits. In the aquaculture industry, Labeo chrysophekadion is induced to spawn using hormones, but this requires huge ponds and controlled conditions.

Lifespan

With proper care, they can live 15–20 years or more, though longevity depends on adequate tank size and water quality.

Behavior & compatibility

Juveniles may appear peaceful, but adults are highly territorial and aggressive toward conspecifics and other large bottom-dwellers. They will often chase or injure tank mates if kept in inadequate space. Only house with equally large, robust species in very spacious aquaria. Best kept singly.

Tank requirements

Tank size: absolute minimum 2500 liters for one adult; 4000 liters recommended.
Aquascape: large open swimming space with solid décor such as rocks and driftwood; avoid delicate plants as they may be uprooted.
Substrate: sand or fine gravel.
Water: stable conditions; pH 6.4–7.6; hardness 9–18 °N; temperature 23–27 °C.
Filtration: very powerful, with high turnover and strong oxygenation to simulate riverine conditions.

🛰️ Why not for home aquaria?

Some freshwater fish sold as juveniles—like the Black shark (Labeo chrysophekadion) or Black pacu (Colossoma macropomum)—can grow to 60–100 cm, become strongly territorial, and demand multi-thousand-liter systems.

In typical home tanks this leads to stunting, stress, aggression, and shortened lifespan. These species are appropriate only for public aquariums or very large custom setups with heavy filtration and ample swimming space.

Want a similar look in a manageable size? Consider Red-tailed black shark (Epalzeorhynchos bicolor) or Flying fox (Epalzeorhynchos kalopterus) instead.