Just a thought. Many tropical fish commonly available in pet stores are bred in very unsanitary conditions in large industrial farms in the Far East. They come in with a myriad of health problems and can be a possible vector of disease to amhibians that have access to the same water as they do. Has anyone considered this posibility when recommending fish as possible companion animals. My suspiscion is that they would actually be worse as disease vectors than cb frogs recieved from a reliable source.Small fish will work well with the redeyes. I think you can be pretty sure (I know thats an oxymoron) that the frogs won't eat your fish. I used to have zebra danios in the pond portion of a Polypedates dennysi tank and they were quite useful. They kept the water pretty clean and the dennysi's (which are much more aggressive feeders than redeyes) never messed with them. There are bunches of tropical fish that would work, white clouds, guppies, danios, even rasboras. Also, the redeyes shouldn't produce any skin secretions that would hurt the fish, which is a problem with people who put fish in with Bombina species. I also had some goldfish in with my common snapping turtle, they were supposed to be food but they turned into janitors, worked out great. @Averhoeven: I know this is divergent from your original idea, but it should work and might be pretty cool.