Roseline Shark (Puntius denisonii)

The Roseline Shark (Sahyadria denisonii), also sold as Denison's Barb or Miss Kerala, is widely regarded as one of the most beautiful large barbs in the aquarium hobby. Native to the fast-flowing mountain streams and rivers of Kerala and Karnataka in India's Western Ghats, it features a torpedo-shaped silver body with a brilliant red stripe from snout to mid-body, a black lateral stripe below, and distinctive yellow and black markings in the forked caudal and dorsal fins.

This species grows to 12–15 cm and is an active, powerful swimmer that requires a large aquarium with ample swimming space and strong water flow. It must be kept in schools of 6 or more; solitary specimens become stressed and may turn aggressive. In a group in a spacious tank, they provide spectacular coordinated swimming displays.

The Roseline Shark is listed as Vulnerable on the IUCN Red List. Overcollection and habitat loss significantly reduced wild populations, though captive breeding programs have made them more sustainable in the trade. Choosing captive-bred specimens is strongly recommended.

They are omnivorous and accept a wide range of foods. Their only demanding care requirements are large tank size, excellent filtration, high oxygenation, and cooler temperatures (ideally below 25°C). In appropriate conditions, they are hardy and long-lived.

Water Parameters: pH 6.5–7.5, temperature 18–25°C, GH 5–15. Cool, well-oxygenated water is essential. Use a powerhead or spray bar return to maintain high dissolved oxygen. Avoid temperatures above 26°C, which cause long-term stress.

Tank Setup: Minimum 250 liters for a school of 6. Provide open swimming lanes, smooth boulders, and robust plants tolerant of current. Sandy or fine-gravel substrate with moderate to strong filtration (10x turnover rate recommended). Secure all openings — these are powerful jumpers.

Feeding: Omnivores accepting quality flake food, medium pellets, frozen bloodworm, brine shrimp, and vegetable matter. Feed twice daily. Spirulina flakes enhance coloration. Varied diet is important for long-term health.

Tankmates: Keep with other robust, similarly-sized peaceful fish tolerant of flow and cooler temperatures. Avoid very small fish, timid species, or those needing warm, still water. Compatible with large tetras, robust loaches, and peaceful cichlids.

Health: Hardy in appropriate conditions. The most common problem is temperature-related stress. Maintain excellent water quality with 30% weekly water changes. Watch for ich and bacterial infections.