The effects of three diets (Diet 1 ‐ with vitamin and mineral supplements, Diet 2 ‐ without vitamin and mineral supplements, and Diet 3 ‐ fish bycatch) and monosex culture (male or female) on the growth, survival, feed conversion ratio (FCR), and production of mud crab Scylla serrata were investigated using a 2 x 3 factorial experiment with three replicates per treatment. Juvenile mud crabs were stocked at 1.0·m 2 in 150 m 2 ponds and reared for 156 days. Results showed no significant interaction between monosex culture and diets (P > 0.05) so that data were pooled by sex and dietary treatment. Mean final body weight of male crabs (427 g) was significantly higher (P 0.05) between the two sexes. Regardless of sex, crabs fed fish bycatch (Diet 3) gave significantly higher (P 0.05). The economic viability of using a diet without vitamin and mineral supplements was comparable to that of a complete diet having about the same cost of production and return on investment of 74 to 75%. The study shows that cost-effective formulated diet could be used as alternative feed for fish bycatch thus saving on feed and storage costs.