Yes, you cannot house multiple species in the same tank. The family name Dendrobitae is all they have in common. Even those in the same genus are spread out and don't interact at all. A bicolor and a terribilis would not interact. Nor would an auratus and a leucomelas. Most dart frogs available today would not see each other in the wild. Even if they did the toxins and secretions and size difference and different behavior would endanger them all