Firstly, can you please set your country in your profile? We require that when you register.

As for keeping darts and mantellas separately, I don't see the harm in it, but I also don't see very much point to it either. Many dart frogs form pairs, to some extent, particularly the imitator group and their close relatives. Even tinctorius pair to some degree. So why keep them apart? What are you own thoughts on this?