There is always a chance that your azureus are/were carrying a disease or parasite that could still be in the terrarium and be harmful to mantella frogs. The safest route to go would be to clean the old terrarium and supplies and throw away anything that can't be cleaned. With my collection a terrarium is designed for one animal and then if I move the animal to a new cage I look at the terrarium as contaminated, assume something is wrong or unsafe in it and then clean it. Chances are that your old azureus terrarium is safe for new inhabitants but there's always a chance that it's not. We shouldn't take these rare frogs out of the wild just to let them die in a contaminated terrarium. Good luck,
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Devin Edmonds
devin@amphibiancare.com
www.amphibiancare.com