If you're an angler, you don't have to leave the city limits to find a place to fish.
Spend a cool morning on the bank of Woodlawn Lake (1103 Cincinnati Ave.), where you'll find carp and channel catfish. You'll also find channel cats in Miller's Pond (6175 Old Pearsall Road) on the South Side, which is stocked annually with rainbow trout as well. The San Antonio River runs through Brackenridge Park (3700 N. St. Mary's St.), where you can drop a line for bass and sunfish.
Make sure to check with the Texas Department of Parks and Wildlife (tpwd.state.texas.us) about picking up appropriate fishing licenses beforehand. The site also has information about when local bodies of water have been stocked.