The present study focused on conducting in silico analysis and investigating the tissue-specific distribution and expression of the catalase gene in platyfish (Xiphophorus maculatus), which can be used as a model organism for studying stress responses in fish. Assay of the steady-state levels of cat gene transcripts by real time PCR revealed. The steady-state level of platyfish cat transcript was abundant liver (2162.21) compared with the level of cat transcript in intestine (1270.94), heart (1241.25), muscle (419.157), brain (46.205), eye (47.57), swimming bladder (28.99), gills (81.18), spleen (95.45), kidney (20.25) ovary (91.16) and testis (113.22). The results suggest that the liver is the major site of cat expression in platyfish, with significantly higher expression levels compared to other tissues. In addition, the research involved using bioinformatics tools to analyze the genetic sequence of the catalase gene and predict its structure and function. The results of the study indicated that the cat in Platyfish shares a high sequence identity and similarity with its orthologs in other teleost species, including medaka, fugu, and zebrafish. This observation suggests that the cat gene is conserved among these fish species, and the gene’s function and regulatory mechanisms are likely to be similar. The high conservation of the cat gene among teleost fish species highlights the importance of this gene in the antioxidant defense system and its potential role in responding to environmental stressors. Platyfish cat gene exhibits a conserved gene structure, as evidenced by its conserved gene synteny with the orthologous cat/CAT genes in other teleost fish and humans. Overall, the study provides evidence for the highly conserved gene structure of the cat gene in platyfish, which contributes to its functional stability and the maintenance of its critical role in antioxidant defense and stress response mechanisms.