Dried skipjack tuna (Katsuwonus pelamis) waste (red meat, gills, viscera, ¢ns, etc.) ). Changes in the nutritional quality (crude protein, crude fat, crude ash, crude ¢bre and nitrogen-free extract and aminoacids) were monitored during a fermentation period of14 days. The proximate analysis showed signi¢cant changes in the composition of L. plantarum-fermented tuna (LPFT) and B. licheniformis-fermented tuna (BLFT) from the unfermented raw materials. Fermentation of tuna waste has resulted in a signi¢cant (Po0.05) increase in the protein content of tuna waste between days 6 and12. All the amino acid contents in BLFT increased during fermentation, whereas, in LPFT the levels of serine, histidine, tyrosine, methionine, cystine and phenylalanine contents were decreased. A marginal increase in calcium and phosphorus levels was recorded in the fermented products. The results of the study suggest that LPFT or BLFT can be used as a novel aquafeed ingredient for di¡erent ¢sh species.