In this study the length–weight (LWR) and length–length relationships (LLR) were carried out for Indus Mahseer, Tor macrolepis, from the Haro River and Nalah Kala, Attock, Pakistan. A total of 118 specimens were used to estimate the relationship parameters. The results of LWR (W = a TLb) from five different sites indicated W = 0.0044 TL3.14, W = 0.0054 TL3.08, W = 0.0059 TL3.21, W = 0.0076 TL3.12, and W = 0.0107 TL2.99, respectively, with an overall value of W = 0.0100 TL2.94. All regressions for LLR were highly significant (P ≤ 0.001), with coefficient of determination (r2) values of > 0.90. All relationships for LWR and LLR were found to be isometric. T. macrolepis is principally a herbivorous bottom feeder, mainly feeding on aquatic plants and algae, supplemented by insects.