Environmental cues are communicated through indoleamine which in turn effects the fish reproductive activities. Seasonally breeders are affected by melatonin where as it effects on aquarium fishes are sparse and ambiguous. Hence aquarium fish Molly (Poeciliaformosa), continuous viviparous breeding species was selected to study the effect of indoleamine, Estrogen (E), Progesterone (P) on gonadotropins. Fish were divided into seven group, 1stgroup as control while remaining 6 groups received 100μg/l: melatonin (MLT), Estrogen (E), Progesterone singly or in combination with MLT (MLT+E or MLT + P, MLT+E+P) for 45 days and were held in L:D 12:12. Hormones assay was done from serum for FSH, LH, GH, E and P. MLT singly or in combination with E or P or only P reduced FSH levels and fish exposed to MLT +E+P had elevated FSH levels. The inhibitory effect of MLT was combated when the animals received all the three hormones simultaneous. LH levels remained statusco when exposed to E or P and significantly reduced in MLT exposed animals an inhibitory effect on LH also. GH levels significantly reduced in treated groups with varied intensities. MLT, MLT+E, MLT+P and only E exposures had significantly reduced P levels but this level was reversed in MLT+E+P or P exposed animals. MLT exposed animals had reduced movement, feeding, segregated in a corner of the aquarium and sexual behaviour was almost nil. Thus, it can be concluded that melatonin has altered gonadotropins and induced physiological hibernation in this species.