ABSTRACT
Concepts of polyculture of Vietnamese koi (Anabas testudineus) with others short cycle fish species especially in the semi-arid zone of Bangladesh helps to increase the production and utilization of water bodies. Optimization of stocking density with and economics of the culture system was evaluated to mini seasonals pond in Rangpur region, Bangladesh for a period 120 days ( 30 April to 30 August) ponds were randomly divided into three treatments with different stocking density, explicitly Vietnamese koi were stocked 74,000 ha-1, 98,000ha-1 and 1,23,000 ha-1 with other fish species in T1, T2 and T3 with triplicate. Fishes were given to commercially available pelleted feed (30% protein). Recorded water quality parameters were within the acceptable limit for fish culture. Sampling was done every fortnightly interval. After 120 days of culture period average harvesting weight was found 198.67±3.28 g, 179.67±9.06 g and 174.33±4.25 g in T1, T2 and T3 respectively. Specific growth rate (SGR) in T1 (4.19) was significantly higher (P<0.05) than T3 (4.07) but less significant with T2 (4.10). Survival rate in T1 (85.3%) varied significantly among the treatment, however total production (kgha-1) in T3 was (17859.96±230.21) significantly higher (P<0.05) rather than T2 (15237.46±669.31) and T1 (13278.91± 78.0) but benefit cost ratio in T1 (1.64±0.03) varied with T2 (1.52±0.0) and T3 (1.40±0.02). It can be calculated that there is a huge potentiality for utilization of seasonals ponds with proper culture technique of short cycle fishes in the semi-arid zone of Bangladesh.