The consensus on the forum here is never to mix species. Everyone's got a million reasons but I would think the biggest reason for you to not mix your dumpy with Red Eye is that your dumpy could get to about 4 inches and the Red Eye could be half that size. I have a tank of Red eyes and they're kind a dainty frogs, thin frogs. That's not how I would describe a full grown dumpy. They're more outgoing and bulky. It would be like the nerd having to be a roommate with the jock. I say keep it all nerds or keep it all jocks. Because the nerd doesn't like to be the football.