The biotransformation of shrimp head waste into ingredients for Nile tilapia (Oreochromis niloticus) post-larvae (PLs) diet formulations was evaluated herein. A novel consortium of lactic acid bacteria, comprising the strains Lactobacillus futsaii LAB06 and L. plantarum LAB14, selected based on kinetic growth parameters, was applied in the fermentation of shrimp head waste. After 48 h, the highest lactic acid production was 100 g L −1 , allowing for maximum recovery of chitin and protein-rich liquor. The liquor was added to commercial powdered fish feed at 15, 30, and 45% (w/w) and offered to Nile tilapia PL during 28 days. The inclusion of 30% provided the best results for Nile tilapia PL survival, weight and length gains, specific growth rate, and biomass, proving that the fermented liquor can be incorporated, leading to economic benefits and contributing to the reduction of environmental pollution caused by the improper disposal of shrimp waste.