Male frogs should reach about 3" in size and female about 4".
Something interesting I read while researching.
"The female expels her eggs with such a force that they go through the deposited sperm cloud and stop up to half a meter away."
"The skin secretions of the frog have antibacterial and antiviral properties that may prove useful in pharmaceutical preparations."
A 2.5' X 1.5' tank will be nice for 2 frogs IMO.
Not that a tank half the size will house 1 frog. They are different from fishes.
These frogs need the space to jump. So 2.5' X 1.5' can house 1 or 2 frogs.