The present study investigates some biological and pharmacological effects of Tetraodon fahaka strigosus (Puffer fish) and Potamotrygon garouensis (Stingray) venom extracts. The saline extracts from skin and innards of T. fahaka strigosus and P. garouensis were used to evaluate haemolytic, enzymatic and in vitro antioxidants activities. In vivo determination of median lethal dose, some blood biochemical parameters and analgesics activities of the extracts in mice were also carried out. The result of this study showed that all extracts from both the puffer fish and stingray showed significantly haemolytic, proteolytic and phospholipase activities. The DPPH scavenging activity of different parts (innard and skin extracts) of puffer fish and stingray demonstrated significantly antioxidant activity at IC50 values 0.16 mg/ml and 0.15 mg/ml and 0.20 mg/ml and 0.01 mg/ml respectively; when compared to the negative control. Median lethal dose range between 31-90 mg/kg body weight. Furthermore, there was significant increase (p<0.05) in the packed cell volume (PCV) and body weight of animals treated with extracts of T. fahaka strigosus and P. garouensis compare to control. The crude extracts from T. fahaka strigosus and P. garouensis administered to mice significantly inhibit acetic acid induced writhing (p<0.05). The results of serum biochemical analysis of animals treated with extracts of T. fahaka strigosus and P. garouensis revealed a significant increase in the activities of alanine transaminase (ALT) and aspartate transaminase (AST) (p<0.05), while no significant difference was observed in alkaline phosphatase (ALP), albumin, total protein and bilirubin. The absorption spectra of T. fahaka strigosus skin and innards and P. garouensis tail and spine sample extracts respectively contains several bands arising from the contribution of different functional groups belonging to proteins, lipids and other biomolecules. The spectral analysis showed variations in composition of biomolecules of the skin, innards, tail and spine samples at a wave number region of 4000-400 cm -1 . These studies also suggest that the extracts of skin and innards from T. fahaka strigosus (puffer fish) and P. garouensis (stingray) have haemolytic, antioxidant and analgesic activities which could be exploited for further therapeutic intervention.