Most good frog sources will say that a ACF should be kept in a 10 gallon.
Talks about the Grow-A-Frog kits that are hardly proper housing for a ACF.
Can a ACF live in a 6 gallon tank? Sure. Can a human live in a closet? Sure. Would either be happy? Not likely.
Please do more research! There are many wonderful frog forums out there and many ACF care sheets and books. Please find them and read up!