Hi Melissa,
Thank you for asking this question first instead of going ahead and finding out the hard way. If you are rescuing another dragon, you should quarantine it to make sure you are not passing parasites or other infections between the dragons. If you are sure your guy is healthy, and you are getting the other dragon from a reputable source who can give you the vet records for your new dragon, it is not as critical, but you do not want to house them together, as they are not social together.
At two and a half years old, Ricco is used to having his own territory and another male would be a threat. A female would be either a threat or a breeding opportunity, and a smaller dragon would make a good snack. I have four adult males, and have them blocked so they cannot see each other. I once had a set up where three of them could see other, and the head bobbing displays and various insults and epithets hurled across the room, while amusing for humans, were deadly serious, and I have not allowed any of them direct contest as they would injure or kill each other.
A male-female meeting would almost certainly involve an attempt at breeding. If he can only see her in a distant tank, he will start running back and forth, displaying his beard, constantly bobbing and acting like a nut, and he may drop a lot of weight with all this display behavior. Even if your girl does not see Ricco, his presence may stimulate her egg production, and you will find her laying infertile eggs, as I experienced with 7 1/2 year old Thorn, thought by her previous owners to be male. On arriving at my home, with my testoserone-rich environment, (5 adult males at that time) she started display female signals, even though there were no males in her sight. She laid three clutches totaling sixty eggs that year, all infertile, as she was not bred.
As far as females together, I have three who want to be Queen B, Nefertiti, Gaia and Emmy, and they make snarky comments to other females when they are present. While I have had females out at the same time, I have to have quick eyes and hands ready to make sure no one gets a quick nip in someone else's direction. I do not risk having any contentious ones out at the same time as the congenial ones, and none of them are housed together, as they are all very possessive of their owns space, and I cannot trust a single one of them to behave like a lady when I am not watching.
There are people who will tell you you can house them together, they done it for years without problem, but as we study and observe more and more is becoming known about the habits of our dear friends, and the solitary method is best for their health and longevity. Ricco may make it to as much as 20 years old, with your love and attention. He will bond with you, and we have plenty of evidence here that beardies loved to be spoiled, and will let you know what they expect from you.
Knowing all of this, if you want to take on a rescue, go for it. There are so many on Craigslist, in shelters or badly misinformed pet stores that desperately need informed homes and the loving care of someone who understands and provides for all their needs.
:love5:
MaryAnn