With the implementation of the new aquatic animal disease reporting in the Asia Pacific region from January 2021, and in lieu of the published QAAD Reports (last issue published was 4^th quarter of 2020), NACA is publishing reported aquatic animal diseases submitted by countries in the Asia-Pacific region. This report covers the fourth quarter of 2023 and the original and updated reports can be accessed from the QAAD page.

In this issue:

• Neolissochilus hexagonolepis (chocolate mahseer): A flagship species for diversification of hill aquaculture in Northeast India
• Aquarium fish culture in open village ponds in South 24 Parganas, West Bengal
• Women nurtured transformative aquaculture in rural Bengal
• Breeding and seed production technology of striped spiny eel Macrognathus pancalus to benefit fish farmers
• Grow-out culture of the loach Lepidocephalichthys thermalis in modified tanks
• NACA Newsletter

This article investigates the ecological, economic, and cultural importance of Neolissochilus hexagonolepis, commonly known as chocolate mahseer and its potential for hill aquaculture in Northeast India. The taxonomy, distribution, and distinct features are described. Chocolate mahseer populations are in decline due to habitat degradation, overfishing and environmental changes, and it is designated as "near threatened" by the IUCN. Breeding patterns, growth parameters, and culture techniques are explored in depth as a candidate species for aquaculture development. Conservation initiatives and the need to balance economic utilisation with species conservation in chocolate mahseer farming are discussed.

The article highlights the successful commercial-scale breeding, propagation, rearing, and sale of aquarium fish species in the Howrah and South 24 Parganas districts of West Bengal, India. It focuses on the innovative practices of two experienced aquarium fish farmers, Sri Bikash Sau and Sri Swapan Parua, who have introduced a novel approach to aquarium fish culture in open earthen and common village ponds. The success stories of Sri Bikash Sau and Sri Swapan Parua serve as inspirations for small and medium-scale farmers and aqua-entrepreneurs. Their innovative approach to open pond production for aquarium fishes demonstrates the increasing potential and expansion of the aquarium fish business in the region.

The striped spiny eel, Macrognathus pancalus, is economically significant but faces population decline due to anthropogenic factors. This study presents a comprehensive approach to breeding and seed production techniques for M. pancalus, conducted at the Regional Research Centre, ICAR-Central Institute of Freshwater Aquaculture, Rahara, India. The study describes broodstock management simulation of natural habitat to stimulate natural breeding. Techniques for hatching and larval rearing, management of early spawn, and precautions to prevent cannibalism are presented. Survival of 88% after one month was achieved. The breeding and seed production techniques provided are suitable for farmers to adapt, and will contribute to the conservation and utilisation of M. pancalus in sustainable aquaculture practices. The findings also highlight the economic potential of this species to provide a nutritious option for consumers at affordable prices.

This study explores the cultivation of the Indian spiny loach, Lepidocephalichthys thermalis, in indigenously designed poly-lined iron frame tanks as a sustainable solution. The article details the fabrication methods for these tanks, highlighting the use of rust-resistant iron and low-density polyethylene sheets.The study proposes a supplementary feed mixture and provides insights into water quality management to ensure optimal conditions. The study demonstrates the potential for achieving a net production level of 1 kg from 400 liters, offering economic viability for farmers. The modified tank-based rearing system is shown to be beneficial in hilly regions with limited land and water resources.

With the implementation of the new aquatic animal disease reporting in the Asia Pacific region from January 2021, and in lieu of the published QAAD Reports (last issue published was 4^th quarter of 2020), NACA is publishing reported aquatic animal diseases submitted by countries in the Asia-Pacific region. This report covers the third quarter of 2023 and the original and updated reports can be accessed from the QAAD page. 

Naihati fish seed market of West Bengal was established in 1976 and is the largest seed market in India. With the advent of induced breeding technology and hatcheries, fish seed is now available almost year-round, catering to the need of Indian farmers. Situated in North 24 Parganas, Naihati wholesale fish seed market is a well-known establishment that provides multifaceted services to stakeholders including fish seed growers, retailers, sellers, and mediators. This article describes the state of the market as aspects of its evolution over time.

In late 2022 tilapia parvovirus (TiPV) was found to be associated with mass mortalities of tilapia in Odisha, India, both individually and in co-infections with tilapia lake virus. Infections have also been reported from Thailand and China. Clinical signs include lethargy, scale loss, redness on the body with haemorrhages on the operculum, base of fins and ventral part, opaqueness of the eyes, swimming near the pond edge and loss of appetite before death. This article describes the epidemiology of TiPV disease including its diagnosis, transmission, prevention and control, and its potential impact on the tilapia aquaculture industry.

The Late Sri Kripan Sarkar was an enterprising ornamental fish breeder-cum-farmer par excellence, exporter and supplier of the same from northern part of West Bengal. As proprietor of Rainbow Ornamental Fish Farm, at Bakshipara Village in Jalpaiguri District, he was an expert and authority in scientific breeding, larval rearing, propagation, research and experimentation on economically important freshwater ornamental fishes. There was a time when Sri Sarkar was the only commercial ornamental fish breeder in north Bengal. This article documents his experiences and career as an influential pioneer in the ornamental fish culture trade.