Yeast supplements and yeast-containing feed ingredients lead to the higher protection against diseases and to the better productivity of fishes resulting in the greater growth of the aquaculture industry. Moreover, rotifers, Artemia, and copepods can be produced well as live aquafeed by application of yeasts in aquaculture. Some yeasts used in probiotic products often improve immunity of fishes as well as attempt to enhance the water quality of aquaculture resulting in good production outcomes. The potential of yeast as probiotic to improve disease resistance has been demonstrated and diets supplemented with S. cerevisiae has reduced mortality in Tilapia after intra-peritoneal injection pathogenic A. hydrophila. Lavi-Sac has developed using quality strains of yeast and provided in micro granular form. The yeast will accrue several benefits to the fish/shrimp as well as pond environment.