I had one for 2 months, he was eating silversides. Something took/bit his tail off and just before he died his hand as well. I'm pretty sure it must of been my fu man chu lionfish as I don't know what else could of done it, they were the only 2 fish in there. I treated the tank with Melafix (to heal him) which unfortunately suffocated my frogfish and killed him
So my advice is don't put any lionfish in with one, and if he gets injured don't use melafix to help heal him. Also try to find one already eating frozen food when you go to buy him. That or be prepared to feed live food. Goldfish guppies are not good for long term, they can be helpful initially to train them to eat silversides, but they do not provide the proper nutrients for over all health. Very small chromis or damsels are ok but too big and the frog can start to choke on them, usually when that happens they'll just spit it back out. If mine didn't start to eat frozen I had thought about setting up a breeding tank for mollies. I would acclimated them to salt water and feed the frogfish the babies. Needless to say it's much easier if you get one that's already eating frozen to begin with.
Also they need a clean tank. I almost killed mine (again he almost stopped breathing) when I stirred up to much detritus off the bottom of my bare bottom tank, trying to siphon the gunk out that was there from the tank sitter over feeding when I went on holidays.
They are also like puffers in the sense that they should not be exposed to air. Netting them and air exposure can damage their lungs and kill them. Some people have done it and not had issues but why risk it if you don't have too.