Virulence of Aeromonas hydrophila in Siamese fighting fish (Betta splendens) and the bacterium susceptibility to some herbal plants

Document Type : Research Paper


1 Program in Aquaculture Technology, Faculty of Agriculture Technology, Rajabhat Maha Sarakham University, 44000, Thailand

2 Animal Production Technology Program, Faculty of Agro-Industrial Technology, Kalasin University, 46000, Thailand

3 Biology Program, Faculty of Science and Technologyogy, Nakhon Ratchasima Rajabhat University, 30000, Thailand

4 Borneo Marine Research Institute, University Malaysia Sabah, Malaysia, 88400 Kota Kinabalu, Sabah, Malaysia


Aeromonas hydrophila was isolated from diseased Siamese fighting fish Betta splendens Regans.  The virulence of A. hydrophiala to Siamese fighting fish was conducted by intraperitoneal injection of two doses of bacterial suspensions with 7.5x107 and 7.5x105 cfu per 0.05 ml. The cumulative mortality was observed in high and low dose groups which showed 98.33 and 20 percent, respectively. Moreover, five medicinal plants extracts namely Centella asiatica, Morinda citrifolia, Melissa officinalis, Piper sarmentosum and Terminalia catappa were determined for antimicrobial activities by broth dilution method. Terminalia catappa extract showed highest antimicrobial effect of MIC and MBC (25 and 12.5 mg/ml), followed by Melissa officinalis and Piper sarmentosum with the same values of MIC and MBC (12.5 and 25 mg/ml).  Finally, Centella asiatica and Morinda citrifolia were similarly MIC and MBC (50 and 100 mg/ml).  It was concluded that five medicinal plants can use to inhibit and kill A. hydrophila in fish.