Species ID I'm no help, but the activity, I've been doing a lot of research on mollusk reproduction, and the 'smoke' is a common characteristic of many species, both the male and female will do this in hope of the eggs being fetilized and settling to grow before they become a snack for another critter or your skimmer scoops them up. The 'smoke' is nothing to worry over unless you had dozens releasing at the same time.

BTW that's a heck of a shot using a flash! Last time I tried using the flash on the tank I was seeing spots for hours and nothing good to show for the efforts. How'd you get away from the reflection?