Cell-cultured fish fat (CCF) has the potential to enhance the flavor and texture of cell-cultured fish meat (CCM). Herein, CCF was developed through the adipogenic transdifferentiation of Larimichthys crocea muscle satellite cells (LCMSCs). A low-serum culture system and a large-scale culture system were established. A rapid transdifferentiation medium was also developed, and the mechanisms in promoting adipogenic transdifferentiation were preliminarily analyzed. The results indicated that the proliferation rate and morphology of cells were not significantly affected by serum reduction following domestication. These cells can be cultured in bioreactors, achieving a 10-fold increase in density. The combination of horse serum and oleic acid enabled adipogenic transdifferentiation within 8 days. Transcriptomic and metabolomic analyses revealed significant changes in gene expression and lipid metabolism, with enrichment of pathways related to fatty acid metabolism. Five inducers were quantified to assess the quality of CFF. This study provides a feasible method for CCF production and lays the theoretical basis for the development of CCM.