I have a very large well established Female GSM. We've had her for the better part of 6 months now and she was probably 3 when we got her from a local reefer. In her early days in our tank she stirred the sand on a continual and annoying basis. Luckily for us the introduction of a GSM quelled her desire to stir the sand immediately.
Last week at MACNA I got the opportunity to acquire a certified male/juvi GSM. He's pretty small. Maybe an inch at best. Still brightly colored with very faint yellow coloring to the stripes. A gorgous specimen. We were nervous about the intro because she's so much bigger than him that she could well have eaten him for lunch. We hung him in the tank in a specimen box after acclimation to see if she would go after him. Suprisingly she all but ignored him.
We introduced him a few minutes later and they have been inseparable best friends ever since. I haven't seen any certifiable mating behavior. No chasing, shaking, kissing, but the host in the same anemone most of the day. He has his apartment still that he tends to visit sporadically during the day but they seem pretty buddy buddy.
I'm hoping to have some mating rituals some time in the near future.
A picture of the happy couple: