Thanks Caspian for your answers.
I thought about native frogs like that but my worries is that the way my vivarium is set I cannot lower the temperature like they would need in the winter.
Also I do not necessarily want a good swimmer (even more I might prefer something that does not like to be in the water too much to be sure my ADFs are safe) I just want something that is not at risk of drowning. Actually I am not even sure that any frogs can drown it is something I heard and I want to see if it is true or not before putting any animal in potential danger