My questions:
How old is the reef tank?
How much live rock?
Do you have a refugium?
What is the gender of the one in the reef now? And what is the gender of the one in the 65g?
If they are the same gender....females ok, two males no!
I have a very established 125 reef tank with well over 175 lbs of live rock, and have a pair of green spotted mandarins with a very "full" refugium. They get lots of pods and will eat frozen mysis, and an occasional treat of brine.
When I put the little female in about 3 months ago the male did beat her up somewhat. He is 2 yrs old and very chubby, she is a baby...only about an inch and a half. He would clamp down on her and not let her go anywhere for the longest time. Thankfully that lasted less than a week. They now swim together, and hunt together. I would have hated to see what he would have done to another male. He found her almost immediately after putting her in the tank even with all that rock to hide in. I put her in on the opposite side of the tank even.