Seaweed has been used in the field of aquaculture as a source of antioxidant, anti-pathogen and immunostimulant. The carrageenan content of seaweed is a potential immunostimulant that can act against bacterial attacks, such as Vibrio alginolyticus on white shrimp culture. This study aims to examine nutrition profile changes in red seaweed Kappaphycus alvarezii after fermentation using Saccharomyces cerevisiae. Fermentation process was done under aerobic conditions at 26-28 ^oC with an agitation of 125 rpm using. The treatments were varied based on inoculum size and comprised of 5% (v/v), 10% (v/v) and 15% (v/v) inoculum, where each treatment was analyzed in triplicates. Crude protein and fat increased in all treatments. The amino acid and fatty acid content rose to ±20% and ±48%, respectively as a result of biosynthesis by Saccharomyces cerevisiae. Fermented Kappaphycus alvarezii is nutritionally more beneficial compared to the unfermented type, supporting its potential as a feed supplement for white shrimp.