Hi, hopefully I can help with the ADF
I am a strong believer that the depth really should not go above 14". These are small frogs who need to breathe frequently - - a constant long distance to swim can tire them out...it may be ok for a while...but if one starts feeling ill then it will not have the energy just to be able to breathe. Some petstores will say that if you have "ramps" then the frogs will follow these to the air - this is NOT true at all so please, if you hear this, walk away.
When you kept them before, what kind of set ups did you have and what was your average life span?
What was the tank temp and diet? A lot of the information pushed by petstores is out dated and made up unfortunately.
And to add to another comment - - an ADF would definitely eat a fish! I have had ADF eat young guppies (not new fry, but a few months old), smaller neons etc. If it can fit in their mouths then it has the potential of being a meal. Shrimp most certainly if caught.
These frogs hunt mostly by scent, not sight, and water movement. They have a lateral line system that senses vibrations in the water caused by a fish's movements. You would be surprised at what they can catch!
I generally always recommend them in a species only tank but guppies are acceptable tank mates- and think of the free food you will have with the never ending supply of guppy fry lol.