Here is the home for my mantellas. I do not run a heater in my system. I am putting them through natural seasons, so right now they are going through a dry, cold season http://www.frogforum.net/vivarium-te...aludarium.html
As far as feeding, not sure what to tell you. Mine eat fruit flies very freely. What were they eating at the shop you nought them from?
And a majority of mantellas in the pet trade are wc. Very few people breed them.