10.22376/ijpbs.2019.10.1.p1-12 Volume 6 Issue 1 2015 (January - March) The most commonly used probiotic is usually characterized as gram positive, non motile, non sporulating bacteria that produce lactic acid as their main by product due to fermentation. The Morphological, Biochemical, Acid and Bile salt tolerance, Haemolytic test are used for identification and conformation of probiotic bacteria. Isolated lessThan i greaterThan Bacillus cereus lessThan /i greaterThan was analyzed using the agar diffusion method, in terms of their general inhibition effects against few human/fish pathogens. The inhibitory effects of lessThan i greaterThan Bacillus cereus lessThan /i greaterThan isolates against human and fish pathogenic bacteria lessThan i greaterThan Eshcherichia coli lessThan /i greaterThan (7mm), lessThan i greaterThan Klebsiella lessThan /i greaterThan spp(8mm), lessThan i greaterThan Bacillus lessThan /i greaterThan spp (5mm), lessThan i greaterThan Proteus mirabilis lessThan /i greaterThan (7mm), lessThan i greaterThan Serratia marcescens lessThan /i greaterThan (12mm), lessThan i greaterThan Staphylococcus aureus lessThan /i greaterThan (7mm), lessThan i greaterThan Vibrio harveyi lessThan /i greaterThan (20mm), lessThan i greaterThan Vibrio parahaemolyticus lessThan /i greaterThan (10mm). In this research, antagonistic activities of lessThan i greaterThan Bacillus cereus lessThan /i greaterThan species isolated from kudukunda ( lessThan i greaterThan Punitus melanampyx lessThan /i greaterThan ) fish sample were studied. S.VIJAYARAM AND S.KANNAN. Probiotics, Lactic acid bacteria, Punitus melanampyx, Bacillus cereus, Antibacterial activity , Periyar lake 60-68