I would still be weary here, Bichir to my knowledge are predatory and quite capable of harming your frog. I know ACF aren't the most appetizing of animals for some fish to eat, perhaps that is why nothing bad has happened.

Glad it is still working out though, there are always exceptions to the rule I suppose.

I have attempted (foolishly) to keep fish (mollies) with my frogs, even apple snails, all were were eaten or harassed to death by the frogs. I keep large female ACFs, perhaps males are less aggressive.