The Guadalupe bass (Micropterus treculii) is a rare species of fish endemic to the U.S. state of Texas,
Its physical traits are very similar to the spotted bass (i.e. small mouth that does not extend past the eye, sleek figure, etc.) with one exception; the green coloring tends to extend lower on the body past the lateral line than their relatives. So far, the record catch is , caught by Dr. Bryan Townsend of Austin in 2014.
Threats and predators
The Guadalupe bass has almost no predators. Its main threat is not predation, but hybridization with the introduced smallmouth bass. The two species are very closely related and in some rivers almost half the Guadalupe bass are hybrids. The Texas Parks and Wildlife Dept stated it will likely stock many bass in the future to beat out the hybrid population. This will be a pilot for several other areas where rare spotted bass subspecies are having the same problems.
Habitat
Typically, Guadalupe bass are found in streams and reservoirs; they are absent from extreme headwaters. They prefer flowing waters of streams within native variety, and use covers such as large rocks, cypress trees, or stumps for refuge. Juvenile fish are often found in fast-moving water but begin transitioning to deeper, moderate current towards the end of their first year.
Reproduction
thumb|Juvenile (top) compared to juvenile [[largemouth bass (bottom), in Texas]]
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 and picks out a gravel nest for spawning in shallow water where there is a high flow rate but out of the way of fast moving water. It is important the male finds a good-looking nest, for these gravel nests attract the females. 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 invertebrates.