Good Frogs for a 20g Long Tank

[Mentat]

One last question before I make my final decision. Would choosing mantella frogs make more use of the space a 20 long provides? Or would the usage be about the same?

If comparing to a Pacman; yes. Majority of Pacman frogs will stay put in their hole and patiently wait for food to come to it. Setting up a tank for a Pacman is way easier compared to a Mantella tank. If you want to create a vivarium with life plants, it can be very rewarding. Take a look at this thread and see if it's something you like: http://www.frogforum.net/vivarium-te...aludarium.html.