I have fooled around on the Guadalupe River...
With a cheap flyrod outfit like you buy at walmart and such. The best fly is one called a wooly bugger...usually an olive green. I have also used some very small artificial worms, maybe about 2 inches long. You can get them at the walmart there in New Braunsfeld. I have caught lots of perch and some Guadalupe Bass. In Gruene there is a fly shop...I have forgotten the name of it, but it is not to far from Gruene Hall. I hope this helps...Vic