I have a new 100 gallon Rubbermaid stock tank, with five goldfish rescued from the feeder tank at LFS. I am trying to think ahead about the winter. Right now the fish are about 2 inches long, but I think they've grown just in the three weeks or so that I've had them. It is going to be possible for me to get them big and fat enough over the summer to successfully overwinter outside? I live in Texas, so the "winter" weather is really not all that wintery. It only gets below 32 degrees a few times each winter and typical weather is 40-60 degrees. Thoughts?

Should be no problem. "Feeders" are comets or commons, which are very hardy. I have three 4" shubunkins that made it through the winter with no problem here in Pennsylvania, where it is quite a bit colder than Texas. There is a ponder in Houston that has even overwintered fancies!