Fifty tilapia nilotica fish samples were collected from local market and tested by PCR technique for the presence of Aeromonas hydrophila which was detected in 36% of the tested sampels . Another trial was performed to find out an effective and safe alternative of using antimicrobials as growth promoters in fish farming in which two hundred and seventy all- mall Nile tilapia fish. The tilapias were treated with of Enterococcus faecium and Bacillus coagulans at a final concentration of (107cfu/ml). 18 aquaria with 6 replicates for treated and controls were used. After 75 days, the tilapias supplemented with the probiotic showed significantly better final weight, body length, specific growth rate, weight gain, feed intake, feed conversion ratio and protein efficiency ratio than those fed the basal diet (Control). After 75 days from experiment start, each experimental fish groups divided into two groups the first group infected with Aeromonas hydrophila while the second group without infection.