Sifter Star Question

[marxsman]

I have Two sand sifting stars in my tank and I actually wrote them off as MIA. But I saw one yesterday and it is missing half of all it's legs. Is he dying or is there a predator that eats these things? The star is probably a few years old.

[Steven Pro]

It could be starving to death, being attacked by some sort of infection, or being eaten. Could you tell us more about your tank? Size, filtration, sand, rock, water quality, other inhabitants, etc.

[marxsman]

The tank is a 6 year old 55 gal reef, 40 lbs live rock and a mixture of crushed coral and sand for bedding that is 4 inches deep. There is a 10 gal refugium, and a (maybe 5 gal) wet/ dry with a protein skimmer. There are 2 96 watt PC light 1 is 10k and other is 50/50 6500k and actinic.
The tank contains 2 clowns, Hippo tang, yellow tang, Mandarin,and two chromis. The water I will test later today. But I do a 5a gal waterchange every week. Also the water showed 0 nitrates, 0 phosphates last week. I have to get new cal and alk tests.