The assessment of fishing resources in reservoirs and the implementation of measures for their management are scarce in Colombia. It is for this reason that the objective of this article is to present information on fishery and management measures for the Porce II, a hydroelectric generation purposes dam. From November 2011 to October 2012, eighteen fish species were collected from the reservoir, nine of which are harvested for food, six of which are exotic. Additionally, a species of shrimp (Macrobrachium sp.) was found to be an important element of local communities’ food security. Sixty-seven fishermen are registered and the annual catches are 238 metric tonnes, 99% of which are tilapia (Oreochromis niloticus and Tilapia sp.). The catch per unit effort (cpue) fluctuated between 8.1 and 34.7 kg/FEU/day (average 15.2 kg/FEU/day). Catches constituted 70% of the local economic income and also contributed significantly to food security to local communities. The two principal species could support higher exploitation levels and there are several risks and uncertainties for the implementation of the fishing management plan formulated for the Porce II Reservoir.