Asian Journal of Fisheries and Aquatic Research

The breeding and growth characteristics of Oryzias melastigma were investigated under controlled laboratory conditions to assess its suitability for aquaculture. The species exhibited a short-generation time of 2 to 3 months that thriving in artificial-seawater at 28°C with a 14-hour light/10-hour dark-cycle. Sexual-dimorphism became apparent after one-month; with males developing a prominent anal-fin, aiding sex identification for experimental-populations. Feeding-experiments revealed that Oryzias melastigma, preferentially consumed early instar mosquito-larvae, showing high feeding-efficiency, particularly on smaller-prey. Additionally, the species demonstrated increased reproductive-success when supplemented with Ulothrix, suggesting its effectiveness as a feed to enhance egg-production and hatchling-survival. The sensitivity of eggs and larvae to pollutants like ammonia and CO₂ indicates the species' potential as a bio-indicator for water-quality. Statistical analysis of reproductive-output indicated that a mature-female, could produce over 1.5 million eggs annually; contributing to aquaculture-systems as a food-source for carnivorous-species. This potential-biomass, when applied to fish farming, could significantly enhance the production of species like Lates calcarifer. The study highlights breeding and feeding behaviour of estuarine rice fish, Oryzias melastigma.