Thirty castrated finishing male pigs were used to evaluate the effects of replacing fish meal (FM) with ensiled Tra catfish (Pangasius hypophthalmus) by-products (ECM) on performance and carcass quality. Pigs were allocated to individual pens and fed a control diet (ECM0) with FM as sole protein supplement, and experimental diets where 100 (ECM100), 75 (ECM75), 50 (ECM50) and 25% (ECM25) of the crude protein (CP) from FM was replaced by the CP from ECM. Feed intake was highest in ECM25 and lowest in ECM75 (P<0.05), and daily weight gain was higher in ECM100 than in the other treatments (P<0.01). Feed conversion ratio was improved (P<0.05) with higher inclusion of ECM in the diets. Carcass yield and dressing percentage were not affected (P>0.05) by treatment, but leaf fat and backfat thickness were higher and loin eye area lower in ECM100 compared with ECM0 (P<0.01). Ether extract and polyunsaturated fatty acid contents and meat colour values in Longissimus dorsi muscle increased (P<0.01) with ECM replacement level. Feed costs were lower in ECM100 and ECM75 compared with ECM25 and ECM0.