Errrr.. you really put your foot in it on this one.
First, Texas angling is ALMOST exclusively largemouth bass in lakes. Guess what Texas doesn't have any of naturally? You guessed it, lakes. Its funny, but true; we gots none. So what we have done, is built dams everywhere possible for flood control and civil water needs, destroying most of the natural systems that those native fish had evolved to survive in. Stock largemouth and hybrid striped bass in these giant freshwater lakes, and you got big business; nothing natural or native about it, but definitely fun.
This has nothing to do with drought, and everything to do with primates playing beaver.
Now, putting a bit harsher light on it, Texas native freshwater fish are fairly unimpressive, given the very marginal aquatic habitats most are built to live in; so its mostly minnow x and minnow y that are in trouble. Other than this one Polyodon spathula
and East Texas is pretty much the Western limit of its range. While its troubling to lose minnow x, the dams are almost certainly the culprit, not climate change or droubts.
nb.. .the largemouth bass that we most fish here, isn't really a native, its a hybridesque monster! (most of its genes are from Florida strains if I recall right) The native black bass is typically a scrawny little river fish.