as far as housing goes. i seriously think you should consider giving the tegu or tortoise its own house. they need to be separate. where are you housing them anyway. you need to soak him/her more often in order for it to shed properly. you can also use olive oil to help out a bit. i also think the diet may be part of it. you put one plate of veggies/fruit for both of them to eat out of or separately? do they have a basking light of some kind? it could be stress related. recheck your husbandry and see if there is something off. but honestly i dont think housing them together is the best move.
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0.0.1 frilled dragon- monster
1.1.0 white's tree frog- popeye, jack
0.1.0 southern painted turtle- ms.tortle
0.1.0 crested gecko- crimson
1.0.0 pinto hedgehog- dante