The Red Bellied Pacu (Piaractus brachypomus) has become a favourite with South Indian diners and fish keepers. Popular in the aquarium trade, the species is a member of the Family Serrasalmidae and Order Characiformes. That makes it a close relative of the infamous Red Bellied Piranha (Pygocentrus nattereri) and San Francisco Piranha (Pygocentrus piraya), fish that have acquired a reputation for killing and devouring human beings. Unlike the former, the Red Bellied Pacu mostly consumes fruits and nuts found on trees making up the floodplain forests of the Amazon and Orinoco Basins. Also famous as the Pirapitinga, it plays a crucial role by dispersing seeds across the floodplains of tropical South America. However, the aquarium trade and surging demand for its flesh have seen it spread to rivers across the world, including South India. Wildlife experts fear that the fish might upset local ecosystems.

Red Bellied Pacu have been found in the states of Kerala, Telangana and Andhra Pradesh in South India.  The species was introduced to India from neighboring Bangladesh between 2003 and 2004. The flesh is a local delicacy with one kilogram fetching up to Rs 200. Such is the demand that farmers have taken to rearing them in private farms despite government concerns and crackdowns. They are fed fish pellets, worms, offal, boiled tapioca, rice, wheat and oil cakes. Red Bellied Pacu have been detected in the Krishna and Godavari Rivers of Andhra Pradesh and Telangana, and the Vellayani Lake, Periyar and Challakudy Rivers of Kerala. The species might even have managed to establish viable populations from individuals escaping aquaculture tanks. Given below is a report from ‘The Hindu’ – ‘South America’s Red-bellied Pacu: A Delicious Alien in Kerala Kitchens’ (dated July 14, 2018) describing the phenomenon:

However, with demand for the fish growing, several local fish farmers in Kerala have taken to breeding the species and ensure a regular supply to the stalls. On an average, the fish fetches ₹200 a kilo. Adults weighing over 3.5 kilos and over 45 cms long are now available in fish stalls across Kerala. The rich and tasty meat of the fish, which is comparable to that of some local varieties, has many takers in the local markets. The fact that no fish diseases were reported during pacu farming has made it the darling of Kerala aquaculturists.

The Department of Dairying, Animal Husbandry and Fisheries is reviewing a report submitted by the National Fisheries Development Board (NFDB) on the risks and benefits of pacu farming. The impact of farming the species was studied in Andhra Pradesh, Kerala, West Bengal and Uttar Pradesh, with the Kochi-based Peninsular and Marine Fish Genetic Resource (PMFGR) Division of NBFGR, conducting the study in Kerala. An earlier study, carried out by N.R. Chattarjee and B. Mazumdar of the West Bengal University of Animal and Fishery Sciences in Kolkata, reported that the pacu was “introduced as an alien species into India via Bangladesh.”

The smaller varieties of pacu have a greyish-silver body with an orange hue that starts from its lower jaw and runs till its anal fin. The adult ones have more of a dark grey body with the orange hue. Experts say the dentition helps them distinguish pacu from its dreaded cousin, the piranha. However, the State Fisheries Department has started acting against the farming of the species. Notices were issued to farmers in Ernakulam, said Deputy Director (Ernakulam Zone) of the State Fisheries Department, S. Mahesh.

Notices were issued by invoking Section 6 (i) of the Kerala Inland Fisheries and Aquaculture Act, which has prohibited the “propagation, rearing and marketing of fish species which is not indigenous.” For the first-time offenders, the Act prescribes an imprisonment of three months and fine of ₹10,000 or both. Though some Kerala farmers had tried farming the banned species way back in 2011, it spread only in the last three years. Agents source seeds from West Bengal, the NFDB report said.

Image Attribution: The image above, is an illustration of the Red Bellied Pacu from the University of Michigan’s Animal Diversity Web page. The Animal Diversity Web is an online database and encyclopedia of animal natural history, built through contributions from students, photographers, and others, for exploring biodiversity and for use in formal, inquiry-based education.

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