The female is chased away by the male and he then stands guard over the incubating eggs.

Both male and female Guadalupe Bass reach adulthood and sexually maturity at one year of age. Their spawning begins as early as March and continues into June depending on the locale and water conditions. However, unlike many other bass, a secondary spawn is possible in late summer or early fall.

The male Guadalupe Bass builds a gravel nest for spawning in shallow water where there is a high flow rate but out of the way of fast moving water. The female lays between 400 and 9000 eggs but is chased away by the male immediately after she lays the eggs. From this point on, the male guards the nest from predators and will not eat, but may strike a lure in order to defend its territory.

The male Guadalupe stays guard over the fry as they hatch. After hatching, the fry feed on invertibrates.

Hybridisation

Pure-strain Guadalupe bass numbers continue to drop after the introduciton of the smallmouth bass with some estimates having the pure-strain population somewhere near 50 percent of the population.

Pure-strain population can now be found near the Pedernales, South Llano, Nueces, Frio, Sabinal, Medina rivers and the Gorman Creek of the Colorado River.

The Texas Fisheries are working towards protecting the pure-strain populations through saturation techniques, which essentially involves introducing large numbers of the Guadalope Bass to crowd out the smallmouth bass.

By the end of 2008, the state had released as many as 200,000 with the same in 2009.

The female is chased away by the male and he then stands guard over the incubating eggs. After hatching, young feed on invertebrates and switch to piscivory as they grow older. Juveniles and younger adults tend to include more fish in their diets than do Largemouth Bass.