In my opinion it's not a good idea to mix... amphibians in general usually secrete toxins from their skin as a defense from predators (thats why they have such bright colors: to warn other animals) and frogs will usually try to eat anything thats smaller than they are (darts are smaller than RETFs) also there is a chance that they could poison each other through the water supply (from the frogs soaking in it to get a drink) or so I've read... and yes thats their latin name...but this is just my opinion and some people mix species and have no problems