Yet, not only Chromis turn the sea into a huge kindergarten...
At the dusk time, shoals of Atherina boyeri fries started to gather by the shoreline.
They form a globe almost reaching a surface and a bottom with it's poles. The globe is hanging still on a place, only turning around it's vertical axis.
If you'd get too close, the globe will get egg-shaped to move a little aside, where it stops and starts twisting slowly again.
These shots were taken by ankle in the water, near the coastline.