I used the term rescue because the six of them were in a 10x10x10" cube with a half dozen Jewels and several small bichirs. Two of them were hanging in the corners of the tank and are very beat up, but have seemed to quickly acclimate to my tank.
I think the brasiliensis guess is a good one and was what I was hoping. I rarely see Geo's in our area and if I do they are certainly not $5 like these guys were!
They are in a 92g corner which is a pretty tall tank and never get more than 6-8" off the bottom. Feeding is mostly them picking at pellets on the sand that were missed by their tankmates.