can i mix any species of frog with crested geckos in my tank?

I am in the process of setting up a exo terra rainforest terrarium (24x18x24). I want to have crested geckos, but I also wanted something quite colourful, and do like the idea of frogs (had in mind red eyed tree frogs). I've researched a bit on the internet and gone in to a few local reptile shops but i'm not really getting a straight answer or its a bit conflicting. just wondered if anyone out there can give me a bit of advice or suggestions about either putting the crested geckos and red eye tree frogs together or crested geckos and something colourful.