We just went through the same process. Brought home a 5 week old Blue, and wanted to introduce him to our 5 month old Arg. Red, and he bit her - just a nip and no latching on. We were just too excited and rushed the intro. They need to settle in to their new surroundings. You only had your fist one for 2 weeks? Yours are both brand new and still getting settled in.
Keep them seperated for at least a couple of weeks. You will want to "quarantine" the new one anyway and observe him/her for any signs of illness etc. Then begin to give them brief, supervised introductions in neutral territory. Watch how they react, and if they are not aggressive toward each other, extend the frequency and duration of their time together. Then put them into the cage and WATCH them again, and go through the same process of introducing them inside the cage.
This worked for us, and after that first time, the two of ours get along like family - OK better than family - like friends. Since the first day we left them in the cage we have always found them sleeping, and sunning themselves together.
Good luck.
MAP
