Is This Tank big enough for 2 African Clawed Frogs?

[ViperJr]

I have been looking at 20 Gallon (90 litre) tanks is that enough room for 2?
Also how often do you feed your frogs and how much of it?
And should i get 2 males or 2 females?

Perhaps not important at all, but 20 gallon is 76 liters (75.7082357 to be exact) and not 90. I'm sorry, I just can't help myself...