A feeding trial was carried out to evaluate the effects of replacing fish meal (FM) with Tra Catfish (Pangasius hypophthalmus) by-product protein hydrolysate (TPH) on performance and carcass quality in pigs. Forty crossbred castrated (Yorkshire x Landrace) male pigs with an initial average bodyweight of 22.8 ± 1.5 kg were allocated to 40 individual pens in a randomized complete block design with eight replications. The pigs were fed a control diet (TPH0) with FM as sole protein supplement. In the experimental diets, 100% (TPH100), 75% (TPH75), 50% (TPH50) and 25% (TPH25) of the crude protein (CP) from FM was replaced by the CP from TPH. The results showed no significant differences in average daily feed intake (ADFI) in all treatments during the growing and finishing phases. However, daily weight gain (ADG) was higher in TPH75 (655 g/day) and TPH100 (663 g/day) than in TPH0 (639 g/day). Feed conversion ratio (FCR) was improved with higher inclusion of TPH in the diets. Carcass yield and dressing percentage were not affected by treatments, but abdominal fat and backfat thickness were higher and in the loin-eye area lower in TPH100 compared with TPH0. Polyunsaturated fatty acids (PUFA), ether extract (EE) contents and meat colour values a* (redness) in the longissimus dorsi muscle increased with TPH replacement level. Feed costs were 10% lower in TPH100 compared with TPH0. In conclusion, replacing FM with TPH improved the performance, but resulted in an increase in backfat thickness and fat content of meat. However, because of reduced feed costs, complete replacement of FM would still be profitable for pig producers in Vietnam.