30 MARCH 2026 • WORLD AQUACULTURE • WWW.WAS.ORG Table 1: Zebrafish Research Maintenance Guide. Parameter Details Determination of Sex Females: Silvery, larger, swollen belly Males: Slim-bodied Breeding Season April to August Breeding Habit Egg-scatterers; eggs are non-adhesive Conditioning Setup Aquarium tank with a perforated divider for separating sexes Spawning Arrangement Males and females introduced on opposite sides of divider in same tank — Spawning ratio: 3 males: 2 females Spawning Tank Setup Water level: 10 cm Temperature: 26–29°C Aeration: 6–8 ppm pH: 7–8 Alkalinity: 50–75 ppm Hardness: 100–200 ppm Carbon dioxide: 0–15 ppm Bottom Substrate Pebbles of 6–8 mm diameter; entire bottom covered Egg Collection Method Eggs fall between pebbles to prevent predation Post-Spawning Protocol Both male and female fish are removed from the tank after spawning Hatching Time 2 days, if temperature is favourable Yolk Sac Absorption Hatchlings take 2 days to absorb yolk sac Initial Feeding Days 3–6: Fed with infusorians Subsequent Feeding At first infusorians then Rotifers, small daphnia (for 1 week) — Then: larger plankton and powdered formulated feed Why Zebrafish Is a Model Organism in Research: A Deep Dive Vatsalya Bhatt and Maharshi Limbola Zebrafish (Danio rerio) have emerged as a powerful model organism in biomedical research, bridging the gap between invertebrate systems and mammalian models. Their utility spans developmental biology, genetics, neuroscience, and regenerative medicine. This article explores the historical evolution of zebrafish from ornamental pets to key research tools, beginning with George Streisinger’s pioneering work in the 1970s. Zebrafish offer unique advantages such as optical transparency, rapid external development, high fecundity, and significant genetic homology with humans—approximately 70% of human genes have a zebrafish counterpart. They are highly amenable to genetic manipulation techniques like CRISPR/Cas9, making them ideal for disease modelling and drug screening. Additionally, their capacity for organ regeneration and complex behaviors enhances their relevance in neuroscience and pharmacology. Despite limitations such as physiological differences from mammals, zebrafish remain indispensable in translational research due to their efficiency, cost-effectiveness, and ethical advantages. This review highlights their growing impact in advancing human health research. Introduction Model organisms play a pivotal role in understanding fundamental biological processes, disease mechanisms, and drug development. Among the various species used in research, the zebrafish (Danio rerio) has become one of the most prominent nonmammalian vertebrate models in biomedical sciences. Its optical transparency, genetic similarity to humans, regenerative capabilities, FIGURE 1. Zebrafish Illustration
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