I have a male & female mandarin pair that never really seemed to even acknowledge each other but tonight just before lights out I noticed them doing a spawning ritual. They were so tight together they looked like they were joined at the hip as they swam up and down.
(ok I know they don't have hips) Well I guess they were more belly to belly & sometimes side by side but always touching each other which is not an easy thing to do in a high flow sps tank.
Anyway it was very interesting & cool to see so I thought I'd share.