Abstract: The short term toxicity in Clarias albopunctatus (Lamonte and Nicole, 1927) exposed to sub-lethal concentrations of Roundup was studied. A total of 36 fish were divided into 3 groups in a static bioassay model. Fish in 2 test groups were exposed to 5 and 15 ppm, respectively, of Roundup while fish in the control group were not exposed to the toxicant. Six fish per group were bled exhaustively (each) at 48 h and at 96 h while the livers and gills were harvested at 96 h for histological studies. The results showed that serum concentrations of total and conjugated bilirubin increased significantly (p<0.05) in a dose-and time-dependent manner. Serum concentrations of alanine and aspartate aminotransferases and alkaline phosphatase were also significantly (p<0.05) elevated in the test fish. Similarly, serum concentrations of creatinine and urea were significantly (p<0.05) elevated in a dose-dependent manner. Histomorphologic studies of the liver and gills showed marked destruction of their architecture in the test fish, thus corroborating the data from the biochemical analyses. Short term exposure of Clarias albupunctatus to sub-lethal concentrations of Roundup was found to be toxic to the fish.