Aquarium Collection Blamed for Decline in Rare Indian Barb Species

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Puntius denisonii, the Redline Torpedo Barb at the Vancouver Aquarium. Stan Shebs/GNU.

Now thought of as endangered in its native range in India, the Redline Torpedo Barb (Puntius denisonii) is disappearing in part because of overzealous fishing to meet demand for the species in the aquarium trade, according to a just-published paper.

Catching Puntius denisonii in India. Image © Madan Subramanian, Indian Aquarist Magazine.

Writing in the current edition of Environmental Biology of Fishes, researchers G. Prasad, Anvar Ali, and R. Raghavan cite various studies of the sleek, highly prized barb apparently documenting dramatic declines in its populations in Kerala, South India. One report from 2004 estimated a 70% reduction in the wild stock of the species in some areas. Indian biologists have described Puntius denisonii as "rare," "very rare," and "endangered," although it is not yet on the IUCN Red List.

Known as "Bleeding Eyes" to Indian fishermen and aquarists, the fish has a string of other names: Denison's Barb, Miss Kerala, Redline Barb, Roseline Shark, Redline Torpedo Fish, and others.

Fragmented Populations

The paper reports that Puntius denisonii is found in "highly fragmented populations restricted to specific pockets" of the Chalakudy, Periyar, Achencoil, Pamba, Valapatanam, Chaliyar, Kallar, Chandragiri and Bharatapuzha rivers of Kerala (South India). They describe it as "a gregarious species" typically netted in rocky pools with thick riparian vegetation.

Raghavan calls the overcollection of the species "Indiscriminate exploitation for the international ornamental trade in a boom and bust fishery. Despite serious population declines, this species is currently exploited on a large scale."

The Indian biologists are calling for limits on the harvest, and for the establishment of no-take zones and protected areas. They say that without better management and conservation "the Western Ghats (South India) is in danger of losing its most celebrated native ornamental fish."

Captive-breds Coming

First exported in 1996, the Redline Torpedo Barb continues to fetch premium prices, but both biologists and aquarists are encouraged by fairly recent successes in captive propagation of the species in Indonesia and Singapore.

Wild-caught Puntius denisonii. Image © Madan Subramanian, Indian Aquarist Magazine.

Matt Clark, editor of Practical Fishkeeping online, suggests that conscientious hobbyists not purchase the fish unless they are sure it is captive-bred, something he acknowledges is not easy to determine, in most cases.

With a high retail price, it would also seem a tempting target for home breeders who can unlock the secrets of getting it to spawn in the aquarium. The species is known to reproduce during the stormy monsoon season in India, and replicating those conditions might be required of would-be breeders.

SOURCE: Prasad G, Ali A and R Raghavan (2008) - Threatened fishes of the world: Puntius denisonii (Day 1865) (Cyprinidae). Environmental Biology of Fishes (2008) 83:189-190.

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