To be honest the rodent part did not scare me as much as the superworm part. superworms should be avoided with pixies as they are excellent at impacting. Plus the frog you posted is a dwarf african bullfrog, they tend to be much more fussy (from my experience) than true giants. I would soak him in slightly warmer than room temperature water, and contain him in an area that he is forced to be warm. 82-84 degrees provides the best results.

I may have missed it but when was the last time he ate and crapped.