32 MARCH 2026 • WORLD AQUACULTURE • WWW.WAS.ORG Neurobehavioral and Psychiatric Research Complex behaviours, such as social interaction, learning, and anxiety-like reactions are displayed by zebrafish. Consequently, their use in neurobehavioral research is growing. Neurological conditions like epilepsy, autistic spectrum disorder, and schizophrenia have been modelled using larval and adult zebrafish (de Carvalho et al., 2025). They are also appropriate for high-throughput behavioural tests due to their small size and high fecundity. Cost-effectiveness and Ethical Advantages Zebrafish are less expensive to keep than rodent models. In addition to requiring less food and room, their embryos develop externally, making observation easier and requiring less intrusive procedures. Crucially, embryos that are less than five days after fertilisation frequently do not have to comply with animal welfare laws, which lowers the ethical hurdles for early-stage research (Kim et al., 2025). High-throughput Drug Screening Zebrafish are perfect for platforms used in drug discovery. In multiwell plates, hundreds of embryos can be arranged and exposed to different substances at the same time. Their modest size and transparency enable automated phenotyping and imaging. As a result, they are being used in toxicology, cardiology, and oncology to screen for treatments (Mushtaq et al., 2025). Role of Laboratory-Scale Recirculating Aquaculture System in Zebrafish Research and Culture To ensure stable conditions for developmental and behavioural studies, laboratory-scale recirculating aquaculture systems (RAS) are crucial. They provide precise environmental control (26–28.5 °C, pH 7.0–8.0, ammonia <0.01 mg/L) through mechanical, bio-, UV filtration, and degassing units (Lawrence, 2007; Harper and Lawrence, 2011). High-density housing made possible by vertical, modular settings and separately plumbed 1–10 L tanks make perfect systems for toxicological and genetic studies (Lawrence and Mason, 2012). By facilitating quarantine and UV sterilisation, which are essential in pathogen-sensitive models, the closed-loop nature improves biosecurity (Lawrence et al., 2012). RAS reduces environmental waste, improves welfare, and uses fewer animals, all of which are in line with the 3Rs (Varga et al., 2018). Sustainability is promoted by long-term savings through water reuse and effective filtering, which solves the problem of higher setup expenses (Ulloa et al., 2020). RAS facilitates a variety of applications, allowing for the integration of instruments such as auto-feeders and imaging for sophisticated research and controlled gradients for replicating environmental stressors (Spence et al., 2008). Adapting Advances in Zebrafish Rearing and Research to Other Aquatic Organisms RAS systems from zebrafish labs are being adapted for hatcheryscale rearing of oysters, seahorses, and ornamental fish (Lawrence and Mason, 2012). Zebrafish spawning and photoperiod protocols are now used as guides for controlled breeding in species like medaka and tilapia (Spence et al., 2008; Lawrence, 2007; Nayak, 2010). Nutritional research on trout, catfish, and prawns is supported by feed trials and gut gene profiling of zebrafish (Cardona et al., 2016; Ulloa et al., 2020). Zebrafish-based FET protocols are now applied to medaka, molluscs, and fathead minnows for environmental risk assessment (Gonzalez-Doncel and Gonzalez, 2020). Imaging and gene-editing tools developed in zebrafish are now used in medaka and killifish to study biomarkers and gene function (Howe et al., 2013; Cassidy-Hanley and Forney, 2017). To increase research capacity in native species like catfish and tilapia, zebrafish research platforms are converted into affordable modules. Limitations The zebrafish model has drawbacks despite its numerous benefits. Zebrafish have a very different immune system than mammals, and they do not have lungs or a placenta. The application of these findings to people may be hampered by these physiological variations. However, humanized models and complementing in vitro systems are being used in continuous efforts to close these gaps (Vaz-Rodrigues and de la Fuente, 2025). Final Remarks Zebrafish have made significant contributions to science, from helping to combat cancer and neurodegeneration to revealing the mysteries of embryogenesis. They are an essential creature in contemporary science because of their cost-effectiveness, regeneration abilities, and genetic resemblance to humans. Zebrafish will surely continue to be at the vanguard of biological discovery as technologies like CRISPR and in vivo imaging advance. FIGURE 3. Unique Characteristics FIGURE 4. Advantages of Lab-Scale RAS for Zebrafish
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