Wandering BTA disappeared

[trilinearmipmap]

Today cleaning my skimmer I found a 1" red disc in the sump with no tentacles. Not sure if it is alive or dead but it smelled OK so I put it back in the main tank.

I hope this is just a split off the original anemone and not the whole thing.

Somehow he went through the slots of the overflow intake, through the 1/4" holes in my standpipe (it is capped at the top), then down into the sump.

Ammonia, nitrites and nitrates are all zero today.

Anyway I feel a little sick about this.