Sahyadria denisonii is an endemic Cyprinid of the Western Ghats of India that has great demand in the international ornamental fish market. The present study examined the morphology, histology and ultra structural biology of testis of the fish. Testicular structure and sperm morphology were studied using light and scanning electron microscopy techniques. Length and weight of testis varied from 16 to 41 mm and from 0.026 to 0.834 gm respectively. Germ cells are seen in different stages as primary and secondary spermatogonia, primary and secondary spermatocytes, spermatids and spermatozoa. A spermatozoon is characterized by ovoid head, a short mid piece, and a single flagellum, but the acrosome was absent. The present study described that S. denisonii has an anastomosing tubular type of testis with an unrestricted distribution of the spermatogonial cells. These descriptions are noteworthy for a better understanding of reproductive biology, for which information remain scarce in the literature.