Inhibins are heterodimeric glycoproteins that belong to the transforming growth factor-β superfamily known to selectively inhibit FSH secretion through negative feedback regulation. Inhibin neutralisation using antibodies or inhibitory peptides offers a promising approach for enhancing reproductive output in aquaculture broodstock. https://www.sciencedirect.com/topics/pharmacology-toxicology-and-pharmaceutical-science/nanoparticleThe Inhibin-α sequence of Oncorhynchus mykiss was retrieved from NCBI (Accession no. XM_021610999.2) and aligned using ClustalW with homologous sequences from Clarias batrachus, Fundulus spp., Salmo trutta, and O.mykiss, O.nerka, Carrasius auratus and Homo sapiens to identify conserved regions. B-cell and T-cell epitopes were predicted using IEDB tools based on antigenicity, surface accessibility, hydrophilicity and flexibility. Out of the many predicted B cell epitopes, amino acid residues from 104-115 were. Similarly, prediction for T cell epitopes was done, and the region 333-347 was selected. The predicted epitopes were validated across various prediction tools. Surface exposure and spatial orientation were further confirmed using BepiPred-2.0 (DTU Health Tech), JSmol visualisation, and SwissModel 3D structural modelling, which located the epitopes on solvent-accessible regions of the inhibin-α protein, confirming their accessibility for antibody binding. The selected epitopic region was synthesized as a peptide, purified, and characterised by RP-HPLC and LC–MS. In RP-HPLC, a single sharp peak was observed at a retention time of 12.73 min. The molecular weight of the peptide was confirmed by LC-MS. The molecular weight of the synthesised peptide was found to be 3086.79 Da, corresponding to the expected value of 3086.16Da. The findings of the study demonstrate successful in-silico design and synthesis of a conserved surface-exposed inhibin-α peptide. The peptide is predicted to elicit a specific antibody response capable of improving FSH-mediated reproductive functions in Oncorhynchus mykiss.