Make sure you have some sort of little cave or hidey hole for the frog. Make sure it is completely smooth and has no jagged egdges, frogs and bettas both are sensitive to these things. Float the frog for 30 mins. See how the betta reacts. If all goes well after the first frog has been in the tank for a while, add a second frog, they do enjoy a friend. ADF's, like bettas, enjoy a temp of 80F so they are good tankmates in that sense.
Feed ADF's frog and tadpole bites and frozen bloodworms/brine shrimp only. I don't think a betta would be interested in the bites, if they did manage to eat one that would probably be trouble for them. Betta's and ADF's are both senstive to illness if not eating the proper foods designed for them. ADF's are also very blind, so feeding in the same place every day is advisabe. I feed my frogs (rotating between frog bites and bloodworms every other day) in there little cave every day. They smell the food and know to go in there to get it. In your situation I'm not sure how tricky it would be to try and get your frogs worms before the betta got to them. That's why I do not keep frogs with fish anymore. They locate their food by smell so when kept with tankmates locating their food by sight they don't stand a chance. Make sure to suck out any uneaten bites with a turkey baster..they get really gross.
