congratz on the new fish.
One thing comes to mind when you talk about the fish you like.
That is the difference in tank requirements. Some barbs extra or a Dempsey will not add that much to your bioload and can be easily added.
But Paroon sharks will grow excessively and become real tankbusters and will require a huge tank.
In the wild they can reach a lenght of 100" (250cm) and up to 300 kg in weight! Although it rarely reaches this size in captivity, it's easily capable of topping 48" (120cm).
So, there's something to think about real good before jumping into the "Monsterfishkeeping-boat"