One coral in my reef turned very pale. And oddly enough, that same exact species is in two other locations and did the exact same thing. It's very light, after shedding its zooxanthellae for whatever reason. I dont know why it did it, and I'll have to see if it survives.
Also, a branch in a birdsnest colony in the back of the reef suddenly turned white, so I checked Alkalinity first and it was 8.5 dKH. Maybe the tongue coral got it and it wasn't a water quality situation. There are a few LPS heads that have vanished while others are happy, and I tend to think this is either coral territorial issues or fish incurred-damage. I've watched a Yellow tang throw a zoanthid frag out of a spot I had it, like it was in its way.
Still, while little things may annoy me, the overall picture is pretty sweet.
This is the new tiny Green BTA I got at the frag swap. Compare the size to those zoanthids... will it grow into a bigger one? We'll see.