Neolissochilus hexagonolepis

Neolissochilus hexagonolepis — the Copper Mahseer — is a large, revered cyprinid native to the fast-flowing rivers of the Himalayan foothills across India, Nepal, Bhutan, and Myanmar. In the wild it is a game fish of considerable cultural significance, capable of exceeding 60 cm and 10 kg. Its common name refers to the distinctive hexagonal scale pattern visible along the flanks, which glint copper-gold in light, creating an armoured appearance of great beauty.

In the aquarium — and truly only in the largest specialist or public aquarium installations — juvenile Copper Mahseer grow rapidly and require progressively larger facilities. They need cool, fast, highly oxygenated water replicating their montane river origin. Temperature must remain below 24°C; warmer conditions cause chronic stress and immunosuppression. Groups of two or more display better acclimation, but the space requirements are considerable.

Copper Mahseer are omnivores in the wild consuming invertebrates, algae, fruits, and smaller fish. In captivity they accept large sinking pellets, frozen invertebrates, and spirulina-based foods readily. Their majestic scale pattern, impressive size, and cultural cachet make them among the most prestigious cyprinids a specialist aquarist can keep.

Water: 16–24°C, pH 6.5–7.5, moderate hardness; very strong current and high oxygen essential. Tank: 1000 L absolute minimum; professional-grade filtration; cool ambient temperature required. Feeding: Omnivore; large sinking pellets, spirulina, frozen invertebrates, blanched vegetables. Breeding: Documented in specialised hatchery conditions only; not achievable in home aquaria. Compatibility: Peaceful giant; keep with large catfish and other robust cyprinids of similar size.