The town center is 12 blocks west of the El Pescadito statue, but there's no real reason to head there unless it is to stock up for your journey at the humongous market at the corners of Arcos Mendes and Ingavi. There are a couple of churrasquerías near the plaza that also serve almuerzos, but none are up to much.
Villamontes is known for its fish restaurants, shacklike structures clustered at the base of the bridge on the road to Yacuiba, which serve freshly caught surubí among other local scalies. You’ll be given the option to have your fish cooked a la parilla (grilled) or frito (fried). Pick the former unless you want the only moisture in it to be cooking oil.