In the field of Sustainable Agriculture, Agronomy and Food Science, escalating costs and ecological exhaustion of wild pelagic forage fish threaten the long-term sustainability of carnivorous aquaculture. This empirical investigation systematically examines Substitution of Marine Fishmeal with Defatted Black Soldier Fly Larval Meal in Asian Seabass Diets through a multi-stage experimental methodology and rigorous quantitative analytical framework. Utilizing eight-week juvenile feeding trials, gut histological evaluation, digestive enzyme profiling, and whole-body proximate composition analysis, data were gathered across multiple operational cycles and validated against established international benchmarks. The statistical and computational results reveal that replacing 50% of dietary fishmeal with insect meal maintained optimal growth rates (FCR = 1.18) with no adverse intestinal inflammation. Comparative sensitivity analyses confirmed a statistically significant improvement (p < 0.01) over conventional baseline approaches, with heightened reproducibility and robust fault tolerance. These comprehensive findings provide actionable theoretical insights and practical implementation guidelines for commercial aquafeed manufacturing and circular insect-protein production industries. Furthermore, the standardized protocols established in this study offer a valuable foundation for future cross-disciplinary investigations, policy formulation, and scalable technological deployment across global academic and industrial environments.