Smallest tank for a frog?

[CherylMatthews]

One of the local pet shops recommended to keep 2 white tree frogs in an exo Terra nano which in my opinion is way too small for one white tree frog let alone two.
Another shop recommended me a bigger terrarium. I have a Komodo medium. Don't know the exact measurements but there's a photo below showing my set up. It didn't cost much either. I highly recommend it.