I agree with Kitti except for adding a second frog in a 10gallon. Greys are slightly smaller and I was told that 2 shouldn't be in a 10 gallon. The 10 gallon min per frog rule is a safer approach... also make sure its in a verticle tank... tree frogs like height... min 24" is recommended. I agree You tube is great for hearing calls XD. I have 1 male and 2 unknowns ... Frodo calls that is the only reason I know hes a male... his size made everyone here think he was a female until he called lol. So size isn't even an exact science either becase my male is bigger than what the care sheet said a male gets too.