Worm Races.
 

The tank is void of fish but I don't want any of God's creatures to starve unnecessarily and I need the critters alive for my tank reset. I noticed what looked a worm race with a Nassarius snail joining in, those snails are fast!! There is a much larger bristle worm near those but out of the picture.
I also saw new things: 2 or 3 whitish "bugs" that were about a quarter of an inch long with a tan stripe on their backs. They had what looked like antennae and legs but I didn't count them. They were quite fast and very skittish, never venturing more than half an inch from the rocks. Strange since I haven't added anything to the tank for almost a year now. I wonder what they were?

Either Amphipods or Copepods.

Amphipods makes sense because of their size. I guess no fish gives them a chance to grow. Thanks!

Yummy treats for Dragonettes.