I don't know if this is written anywhere in the other posts, or if maybe we can edit the first posting, but I just learned by terrible experience that some ADFs eat betta fins.
I just got an ADF and after all of the extensive research I did, all I ever found was that you have to be careful about the betta's behavior around the frog and not vice versa. 2 days in the tank with my betta were enough to destroy his caudal and part of his anal fin. I actually caught the frog jump up and rip a piece of fin off.
I just wish that I had found somewhere that would have said this when considering putting ADFs and bettas together, or else I never would have gotten one. Now the poor frog has to live in a 1g quarantine I have makeshifted, my betta's going to have to heal for a while and I'm just very discouraged about getting tankmates.
Edit: I do see one line in the initial posting about ADFs eating fins. I wish it were more prominent. ]=