There are three types of Mantellas I would love to own (haven't bought any yet): blue legged mantella (mantella expactata), painted mantella (mantella baroni) and the black-eyed mantella (mantella milotympanum). Are these difficult to find? Can these possibly share the same vivarium?

I am new to this, so I am sure this will appear as a stupid question to you experienced herpetologists, but I have a keen interest in frogs and would be very interested in learning more. Ed