I can see several issues with this, not necessarily insurmountable ones, but worth pondering.
Firstly, you'll get a lot of splashing, and a lot of evaporation, from moving warm water, so it'll need topping up a lot more than you'd probably expect.
I also can't see any way of keeping a frog in just one section, or fish in just one for that matter, they will mix, so they'd need to be compatible regardless.
Unless the tank is big then you've got very little water volume there, so you'll be very limited on stocking.