Mandarinfish stay hidden away beneath their coral rubble homes during the day but at dusk, they become active and mate. The male (the larger of the two) has a harem of females and mates once with each of them.
When the time is right, the pair rises just a few inches above the corals and simultaneously release eggs and sperm into the water column.
To capture this image, I had to wait for this pair to begin rising and then get low so that the background had no corals in it.
I love Mandarin. They were my favorites in my saltwater aquarium, beautiful and not "flighty". You've captured the colors very well!