Nice I'm not sure what type it could be either due to my lack of knowledge of Texan ants they grow really fast which is a plus only two things to be careful of 1:they sting 2:solenopsis are escape artists so be careful and stay ontop of them
Two names to look up though to see which specie it could be are
1:Solenopsis Invicta
2:Solenopsis Geminata
1 because they are he RIFA ants that spread like crazy and are everywhere in the south and 2 because they seem to be the most common native fire ant in texas