The Acehnese mahseer, locally known as keureling, Tor tambra is one of the highest economically valued freshwater fishes found in Aceh waters. The culture of T. tambra was initiated in Aceh Province, Indonesia more than five years ago. However, the growth rate in captivity has been low, probably due to feeding problems. Hence, the objective of the present study was to evaluate the optimum level of dietary protein in commercial feeds for growth improvement. Three commercial feeds with different levels of protein i.e. 20%, 25%, and 30%, were tested in this study. A total of nine semi-concrete ponds were used and each pond was stocked with 15 mahseer fingerlings. The experimental fish were fed at a ratio of 3% of body weight twice a day for 60 days. The ANOVA tests revealed that dietary protein levels significantly affected growth performance, protein efficiency ratio, protein retention efficiency and lipid content in carcass but did not significantly affect survival rate and protein content in the carcass (p>0.05). The results showed that the growth performance, survival rate, and protein content increased with increasing protein level in the diet and the best composition was 30% of protein.