The objective of this study was to know the sanitary quality of fish coming from Layo farm. Twenty fishes (Oreochromis niloticus), were selected in four ponds and Escherichia coli were isolated in gills and viscera according to microbiological methods. One hundred and twenty strains of E. coli were isolated, and their virulence was performed by polymerase chain reaction (PCR) using specific primers. Eleven (11) strains (9.16%) including 7 strains of gills (11.66%) and 4 strains of viscera (6.66%) had virulence genes eae, Stx1, Stx2 or ial. Atypical Enteropathogenic E. coli (EPEC, eae+, lack of bfp) was isolated from gills (5%) and viscera (1.66%). Shiga toxigenic E. coli (STEC) with genes eae + Stx2, Stx1 and Stx2 were isolated in viscera (5%) and gills (3.33%). For Enteroinvasive E. coli (EIEC), ial gene was isolated in gills (3.33%) but no ipah gene. Enterotoxinogen E. coli (ETEC) with lt gene and Enteroaggregating E. coli (EAEC) with aggA gene were not detected in this study. This study revealed that some fish from Layo farm are carriers of virulent E. coli that can cause serious human diseases and can lead to consumer death if cooking is insufficient or by cross-contamination. This therefore poses a real public health problem.