Thanks.
I'll try to get a better photo later this evening with my tripod.
But it seems I was mistaken when I said that it doesn't move. This morning it looks like the two patches became one larger patch... ?
And another small patch in another part of the tank is gone with only some of those small white ovals remaining...
Maybe they were eaten.
This morning my sexy shrimp appeared to be eating stuff around these things. But almost looked like he was tending them. Not destroying.
Bah.