I have given you the wrong impression. Serpents/Brittles are for the most part reef safe. What they are doing is natural to them and more a product of their physical strength than their predatory nature. There are many many hundereds of stars though. Green Brittle Stars for example are known to ambush fish at night once they attain a large size. But whats really most likely going on is that your free floating shrooms are coming to a rest near a den/burrow. And that the Star in question is probably attracted to that area where alot of debris of various consistency comes to rest. And it just grabs hold of the shroom like it does anything else. Substrate, small rocks, shells, gravel, you name it. Slowly it passes over everything gloaming whatever it can. They drop inedible stuff (at their mouth) and slowly ingest whatever debris they can. You will probably find a collection of shrooms hopefully. Shrooms are most likely not edible to the Star. In all cases where I lost shrooms, they were free floating. When I finally caught on I recovered them.
As I sit here and ponder I wonder what causes so much floating I wonder if your current isn't to high. Contrary to most opinions, corals like to eat and shrooms are no exception. Good current flow does not allow them to easily obtain and move the small kinds of foods they like to eat, as opposed to say a filter feeder. The shrooms you list do not require large amounts of light so you may wish to ensure that they are in a lower flow area in your tank. I've noticed they let go in heavier flow areas and reattach in the slower areas where they can finally come to rest. Those areas coincidentally are where alot of debris comes to rest.
Tall
