Micropterus treculii is a rare species of fish endemic to the U.S. state of Texas, where it also is the official state fish. It is restricted to creeks and rivers (including the Guadalupe River, hence the name Guadalupe Bass), and is listed as near threatened. Today, most fly fishermen and anglers practice catch-and-release techniques to improve fish populations. The Guadalupe Bass is often difficult to distinguish from the smallmouth bass or spotted bass and the fish is known to hybridize.

Guadalupe Bass, like most black bass, are lime to olive green in color, this particular species being lighter in shade usually in river specimens. They have a lateral line covered in mostly separate diamond shaped or circular spots, which with age fades from black to olive.

There are also many smaller diamond marks scattered on the back which are less distinguished than the ones on the lateral line. Its physical traits are very similar to the spotted bass small mouth that doesn't 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 cousins. So far the record is 3.71 lbs (3 lbs 11.360 oz.), caught by Dr. Bryan Townsend of Austin in 2014. The fish is only found in Edward's Plateau in central Texas. Its main habitats are the San Marcos, Colorado, Llano, and Guadalupe rivers.

More Info: en.m.wikipedia.org