Thanks! I was thinking of the guppies, since they are easier and fast breeders. If I did this, I would put them in an aquarium of their own. I know they have water conditioners out there for reptiles, but have never tried any of them. I use bottled water in my water dragon enclosure so I don't really need to condition that water. I figure, in the wild these guys would have access to fish, so having one every now and again might be interesting.
It's still up in the air for me, but I thought I might ask. Thanks for your opinion, it is truly valued.