Eighteen specimen of Oreochromis niloticus was procured at Olomore fish market Abeokuta, Ogun State, Nigeria. The length weight relationship, morphometric and meristic measurement was studied on the samples and they were also examined for bacteria pathogens from the gut, gill and skin of Oreochromis niloticus by asepitically removing and weighing 1 gram each of the skin, flesh and gut for the test. Serial dilution was done to give 105 dilution of the original stock culture. The cultural, morphological and biochemical characteristic of the isolates were done. The different bacteria were isolated and tested for their sensitivity to different anti biotics. A total of four (4) bacteria were identified (Salmonella sp., Escherichia coli, Streptococcus faecalis and Staphylococcus aureus)). The one tail T-test conducted for combined and separate sexes of Oreochromis niloticus showed that there is no significant difference in the weight of the sexes (87.93) with the range of 1.17 to 168.6. The meristic count showed no significant difference in both sexes as the dorsal spine (1) in both sexes, dorsal ray (6-7) in both sexes, pectoral fin ray (8) in both sexes, pectoral spine (1) in both sexes, pelvic spine (0), in both sexes, pelvic ray (10-11) in both sexes, Anal ray (8-9) in both sexes, anal spine (0) in both sexes. The bacteria count in the gut of the present study recorded the highest in the male (1.53) and female (1.37) Oreochromis niloticus.