Funny anecdote about sand sifting stars:
I had a huge bristle worm overpopulation in my 75 quarantine tank.
Everyone, said, "You must be overfeeding." "They are natural, leave them alone." "They are eating something, or they would not be there." etc.
But they were not simply numerous, they were ridiculous. Not dozens, but hundreds. I finally purchased some worm traps, but work was pressing and I didn't get the traps in right away.
Then the tank crashed. I think there were only a couple fish and no inverts, so it was no big deal. I did a good cleaning, replaced water, etc. and was good to go.
But I never figured out what they were eating. The two fish were fed very lightly.
Then I remembered the two sand sifting stars I took from a customer tank two months previous. I could tell by the way they were acting they were starving, (crawling up the glass, etc.) so I took them home and promptly forgot about them.
Apparently, dead sand stars are good bristle worm food. But when they are gone, all the worms die, and the tank can crash. :headwally: