This study exploits the threshold of the mangrove Acanthus ilicifolius, sea holly, as an ingredient of food of Poecilia sphenops, black molly. In various recent studies, Acanthus ilicifolius have been proved to be of high medicinal property though it is being used as traditional medicine among the tribes since very ancient times. The powder and silage form of the leaf substituted 25% of fish meal in the fish feed in two tests separately. The growth indicators such as Specific Growth Rate, Feed Conversion Ratio, and Condition factor were calculated and recorded after 45 days of observation. Specific Growth Rate, Feed Efficiency Ratio and Protein Efficiency ratio were significantly (p<0.05) greater in control group than experimental feed group. Biochemical indicators like fish tissue protein and glycogen were also examined at the end of the experiment and found to be greater in experimental feeds at significance level 1%. Protein was highest among the fish fed with leaf silage diet and Glycogen was highest among fish fed with leaf powder diet. Both leaf powder and leaf silage diet proved to be successful as feed ingredient.