They will not eat feeder fish and are fine with a lot of water in their tank. I had 6 white's in this tank until I had to take it down due to a construction flaw http://www.frogforum.net/vivarium-te...aludarium.html

As far as mixing the white's and fbt's aside from the whole toxins in the water issue, which I, personally, am still 'iffy' on, they have different husbandry requirements and wouldn't be suitable tank mates. Now, if you could find a terrestrial frog or toad from the same region, then possibly. But I wouldn't recommend mixing species. This should only be done by expert keepers with years upon years of experience. There is way too much to go wrong and inexperienced keepers can miss theist subtle indication that there is trouble in a mixed enclosure.