The objective of this study was to evaluate the particulate matter uptake, survival, condition index (CI), and proximate composition of Crassostrea gigas, cocultured in seawater with tilapia. We used three densities of oysters (two, four, and eight) and one control (no oysters) per 150 g of tilapia biomass. Water quality parameters were measured daily, whereas NH 4 -N, NO 2 -N, NO 3 -N, PO 4 , total Kjeldahl nitrogen (TKN), chlorophyll a (Chl a), total suspended solids (TSS) proximate composition and CI of C. gigas were determined at the beginning and at the end of the study. No significant differences in nutrient content were observed between treatments. Significant differences were observed in TKN, Chl a, and TSS between the control and the oyster tanks. Maximum removal percentages were 43.16 for TKN (two oyster treatment), 80.23 for Chl a, and 73.55 for TSS (both in eight oyster treatment). Survival of C. gigas was 100% in all treatments. Significantly higher growth was only observed in two oyster treatment. Protein and carbohydrate content in the oyster tissues diminished in all treatments, whereas lipid increased in treatments with two and four oysters. These results indicate that TSS produced from tilapia can be used as a source of food for C. gigas.