The immunomodulatory effect of Bacopa monnieri (Brahmi) in enhancing stress tolerance in Labeo rohita (Rohu) have been demonstrated in this book. The effect of Brahmi on the specific activities of the antioxidant enzymes, superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx) in Labeo rohita fingerlings fed with Brahmi incorporated feed and to study the changes in the activities of these enzymes after exposure to low temperature stress.