Chloramine T (Cl-T) is a low toxic disinfectant used in the aquaculture industry both culture and processing. However, it is toxic to fishes and prawns. Therefore in this study, a 28 day growth trial was conducted on the fry of Cyprinus carpio (initial length:  2.25 ± 0.029 cm; initial weight: 0.43 ± 0.039 g) using three types of formulated diets. The diet-I was formulated without Senna auriculata as an ingredient, diets-II, and III were with S. auriculata leaf, and flower, respectively.  These three diets were fed to the fish to assess the growth promotion potential of S. auriculata, and to understand the amelioration of Cl-T by S. auriculata while assess the sub-lethal toxicity of Cl-T at three different concentrations (25, 50, and 75% of the 96 hr LC50, i.e., 6.16, 12.33 and 18.50 mg/L, respectively). The diet formulated using S. auriculata has yielded better growth and survival of fish in comparison to control (p<0.05); among the two plant parts, the flower has performed better than that of the leaf. Regarding the sub-lethal toxicity of Cl-T, the concentration dependent decrease (p<0.05) in growth and survival of the fish was recorded. Regarding amelioration of Cl-T toxicity, S. auriculata flower has mitigated better than that of its leaf when the fish was fed, respective formulated diets when compared with control. However, the elevated response in growth and survival between leaf and flower of S. auriculata included groups was not statistically significant. Actually, the growth and survival in S. auriculata included diet fed fish groups were improved over control (S. auriculata un-included group). These observations indicated the fact that S. auriculata flower has more growth promoting potency than that of its leaf in C. carpio. Similarly, S. auriculata flower has more ameliorative potency against chloramine T than that of its leaf. Therefore S. auriculata can be used in aquaculture of fishes to promote sustainability.