Yeah... a LOT of people keep them together with no problems, but it really seems to depend on the personality of the fish - some seem to care more than others about frogs in their tank. If you do decide to try, I'd keep a very close eye on things for the first month or two, and have a back-up tank ready to move either the fish or the frog into permanently, if any problems arise. Feeding can also be troublesome in a tank with fish and frogs. ADF don't see very well, and tend to take a while to find and eat their food, while betta eat quickly, so you may run into problems with over-feeding your betta and under-feeding your frog. There are ways around this - you just have to be wary of the possibility of a problem. My betta and my frog(s) have always been in different tanks, but Speckles WAS in a community tank with other types of fish at one point, and for me it was easier to move her into her own tank. Gizmo and many others are able to rock a frog/fish tank with ease, though!