Asterina stars all gone??

[Reef Pilot]

I just noticed that all my asterina stars have disappeared from my DT. Had them for years, and now suddenly all gone. In fact my tank was over run with them, and used to wonder how I could reduce the population. I guess I don't have that problem anymore. I did a pretty good search, and can't find a single asterina.

But just wondering what would make them all go away in such a short time. I have not added any new fish for a while. The only major change, is more coral, mostly SPS, and a few LPS. Maybe they are stinging them to death??

I should mention they are still in my sump, so it has nothing to do with the water. I assume something must be eating or killing them in my DT.

Any ideas?