An experiment was conducted to evaluate the perusal of herbivore fish, Barbonymus gonionotus (commonly called as java punti or gonionotus) for savaging bio-fouling organisms and salvaging production efficiency, in cage polyculture with Pangasianodon hypophthalmus (pangas)in a tropical Indian reservoir, Salia, Odisha. The polyculture experimental setup followed Randomized Block Design (RBD) in five treatment group of species ratio of pangas and gonionotus: (P:G) 80: 20 (T‐1), 60: 40 (T‐2), 50:50 (T-3), 40:60 (T-4), 20:80 (T-5), and monoculture of gonionotus and pangasius designated as T-6 and T-7,respectively. All the experimental treatments carried out in two replicates. Stocking density was maintained @ 50no./m3. Growth and survival of gonionotus and pangasius was found significantly (p<0.05) higher in T-1 (80:20, P:G). The growth of biofouling organism is completely controlled in cages stocked with gonionotus. Plankton and periphyton density was also found lower in polyculture and monoculture of gonionotus than the monoculture of pangas. The food selectivity index of gonionotus indicated positive preference towards the biofouling organism while pangas shows negative preference (value). Thus, present study suggested that 20% incorporation level could enhance production efficiency in commercial grow‐out pangasius cage farming on one hand, and pave a prolific way for creating a green environment by salvaging the inland cages through savaging the biofouling organisms for sustainable cage farming in tropical reservoirs on other hand.