Also as Rocksor said, if it's only eating feeders that is another issue in its own right.
I am assuming it's feeder goldfish from a local fish store? That is a bad thing to do, many times they will be full of diseases that can get your Texas sick as well. Its best to get it on a good pellet instead.
Live food alone is not a good diet, in the wild they eat all kinds of stuff, from other fish, to crustaions, to plantmater as well. How would you like eating chicken legs only for life.
After you get it on pellets you can then give it treats like frozen blood worms, brine shrimp, earthworms, and the like.
Now if you really want feeders, it's best to raise your own so you know they are safe. There are choices, livebarers like Swordtails or even Convicts.