Carbohydrases have perhaps excited the most interest of all the enzymes, particularly because salmonids do not handle the large carbohydrate molecules very well, and many workers wanted to determine the reason. Further, because there are several carbohydrases, the possibility that different enzyme combinations might show adaptations to different diets also intrigued some investigators. Also, herbivorous fish might be expected to have more carbohydrase activity and less tryptic activity than carnivores or omnivores.