Today, more attention is focused on the use of medicinal herbal extracts to improve yield in aquaculture as alternatives to chemical agents. The present study evaluates the antioxidant and antibacterial activity of floral extracts of Leucas aspera and Moringa oleifera  against  Aeromonas hydrophila and Vibrio parahaemolyticus, the most common fish pathogens. The presence of bioactive compounds was confirmed using GC-MS/MS analysis. Antioxidant activity was analyzed using the DPPH assay. The IC50 value for free radical scavenging by Moringa oleifera flower extract and Leucas aspera flower in Oreochromis niloticus were 36 µg/ml and 73.89 µg/ml respectively. In in-vitro antibacterial analysis, both the extract at 10 mg/ml concentration showed activity against fish pathogen namely, A. hydrophila and V. parahaemolyticus. The M. oleifera flower extract showed maximum zone of inhibition (25mm, 40mm) and the L. aspera flower extract (21mm, 35mm). Plant extract based formulated fish feed could, therefore, be used in aquaculture, as a potent substitute against antibiotics for disease management.

Moringa oleifera, Leucas aspera, Aeromonas hydrophila, Vibrio parahaemolyticus, Oreochromis niloticus, antimicrobial