I am a happy owner of two pacific tree frogs. The first, a male named Pluto, I rescued from a blueberry picking machine a year ago, and the second, a female, my dad just caught for me today. I'd love to put them together to give Pluto some companionship, but I have a few concerns.

Is there any risk of aggression between a male and female?
How much space is enough for the two of them?
Does my male frog even want a girlfrog friend?

Also I'm a little worried because Pluto stopped doing deep, loud croaks about six months ago and only does occasional, little, very quiet chirps. Should I be worried (I am)? I thought maybe he had given up hopes of attracting a woman and that a girl frog would renew his vigor.
Thanks!