Housing different localities of the same species can work but there is always the chance that they will breed which is frowned upon in the PDF community but its your choice :).
Also keep in mind that some species of dart frogs are aggressive towards the same sex. Like Tinc females are the...
I personally would use a low wattage bulb for ambient temps. Seal in the enclosure so now heat or humidity gets out. Heat pads suck at keeping the air temp up.
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Do not put to much pressure on the little thing. Give him time.
No I don't sell them and have never kept them. I would buy a stock tank tbh. Cages you find in pet stores are not suitable for monitors. They can be modified for babies but not adults. I'd recomend joining a reptile forum or a varanid forum.
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Or you can just order F/T mice.
Look into ridge tail monitors Varanus acanthurus. Stay pretty small and from what I understand not to shy. But they need several inches of burrowing space just like most monitors. The good thing is that all that you see for sale are CBB.
I would go with a tegu, there are more successful keepers of tegus then there are on monitors so getting good info on them is not to hard.
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Also most if not all rough necks are wc.