I'm glad you were the first to bring this up Lija. I will follow your lead. African Bullfrogs are not classified, nor found in nature as an aquatic species or even semi aquatic. Their needs cannot be fully met with an all water setup.

Now take a semi-aquatic species for example, Fire Bellied Toads. They will not die if they are kept in moist substrate, are their needs fully met, not so much. I could go on and on with examples of how animals will survive in different instances, but the fact still remains; you may have short term success with an all water setup, but are you really meeting the animals needs? It does not have a choice on how you house it.

As far as fish go, I personally would only use fish that I bred myself. Most fish obtained from pet stores are a vector for parasites/communicable diseases.