L.vannamei of body weight 6.5�0.5 gms were selected to study the mortality rate, mean survival time, O 2 consumption, unit metabolism and excretory pattern on exposure to different ranges of both acidic and alkaline pH media. At pH 3.5and pH 10.5 highest mortality (100%) and least mean survival time were observed. At pH 4.5 and 9.5 50% mortality was observed 71 hrs of mean survival time was observed at 4.5 pH where as at pH 9.5 mean survival time was 84 hrs which was highest O consumption, unit metabolism, ammonia, ammonia/oxygen were estimated. In 2 both acidic and alkaline exposed prawns O consumption and unit metabolism were reduced over control. The 2 reduction was less in alkaline exposed prawns. But the ammonia content was increased in alkaline exposed prawns where as reduced in acidic exposure. The similar trend was observed in the case of ammonia/oxygen ratio.