This study examined the varying levels of thyroxine hormone impact (at doses of 2, 10, and 50 µg g-1 BW) as an environmentally responsive hormone on the fatty acid and sexual steroid profiles in male Labeo rohita fish. Each treatment group comprised six male fish with an average weight of 5.4 ± 0.58 kg. Blood samples were collected from male rohu fish pre-and post-injection, as well as following sperm retrieval from the caudal peduncle. Biotechnical parameters were evaluated post-fertilization. Among male breeders, the pituitary treatment and the 50 µg g-1 BW thyroxine treatment exhibited the highest levels of estradiol, testosterone, 17-alpha hydroxyprogesterone, cortisol, LH, as well as testicular protein and fat content. Whereas the lowest levels were observed in the LHRH recipient and control groups (p < 0.05). Moreover, the saturated fatty acids C16:0 and C18:0, monounsaturated fatty acids C18:1n9c and C24:1n9, along with polyunsaturated fatty acids C20:3n6 and C22:6n3 in male breeders, were found to be the predominant fatty acids in the testes under hormonal treatment. The pituitary treatment and the 50 µg g-1 BW thyroxine treatment demonstrated a greater total percentage of testicular fatty acids compared to other interventions (p < 0.05). These findings emphasize the heightened efficacy of pituitary hormone and subsequent thyroxine hormone administration at a dose of 50 µg g-1 BW, relative to lower thyroxine doses and LHRH. The aforementioned treatment can increase the levels of sex hormones that are important for sexual responsiveness, emphasizing their pivotal role in facilitating successful artificial reproduction in male Rohu breeders.