[JasonE]

In my opinion there are too many variables to say that any specific size of tank is the "optimal" size for a given species unless you just list the largest readily available sized tank for every species.

Agreed. You should give your frogs as big of a tank as possible.

Personally I don't think 18" in height is appropriate for any dart frog. Also, I don't think a footprint with a 12" measurement is enough floor space.

 

[JasonE]

18x18x24” seems to be the smallest acceptable dimensions for adult frogs of any species.

No. There are many species that that size enclosure is too small for. In particular terribilis.

OP - You asked us what the recommended size enclosure is for frogs. The answer is 36x18x36" because the frogs deserve the largest enclosure possible and it is the largest, affordable size out there. Many of us have 36" exos. You can check my threads to see my tanks. Neither of them are under 36" high.

What people recommend and what are acceptable are two different topics. Keep in mind what you asked before getting upset at the answers.