I have paddled and fished rivers in Texas my whole life. For the spring fed hill country rivers like the Llano, San Marcos, Guadalupe, Medina, Frio, Devils.....I have never found a bait that catches river bass quite like a curley tailed grub on a jig head! Not the tiny crappie jigs but a 3”-4” curley tailed grub on a 1/4oz jig head with a decent sized wide gap hook. Any color....as long as it’s chartruse!
Many other baits can catch river bass but my experiences have been that if they are bitting anything they are bitting this swimming jig set up. Even during low water conditions pay extra attention to areas of moving water and especially the pools at the base of a set of rapids.