Abstract: This paper embodies the antibacterial activity of aqueous extracts of three macrophytes Polygonium amphibium(leaves, rhizome), Potamageton pectinatus(leaves) and Ipomea aquatica(leaves, rhizome) against fish pathogen Pseudomonas aeruginosa isolated from freshwater fishes. During the study it was found that the strongest antibacterial activity among the above mentioned macrophyte species were obtained by the aqueous extract of Polygonium amphibium(leaves) with inhibition zone of 12.9mm followed by Polygonium amphibium(rhizome) with inhibition zone of 12mm. The aqueous extract of Ipomea aquatica(rhizome) marked 9.7mm inhibition zone followed by Potamageton pectinatus(leaves) with inhibition zone of 8mm while Ipomea aquatica(leaves) marked 7mm inhibition zone against Pseudomonas aeruginosa