Help identify this star fish please

[DirtinLa]

They were sold to us as sand sifters and we know they are not. So what are they please?

Are they reef safe?

 

[Bongo Shrimp]

They are Iconaster longimanus. It's not known exactly what they eat but it's thought that they scavenge and eat detritus. To maintain one in the long run, you should have a large tank with lots of live rock. For multiple individuals you should have a very large tank or they will outcompete each other for food. Also, like many other stars, they can take a year or more to starve so it can be hard to determine how healthy they are at a given time.

 

[Calappidae]

+1^

In addition to that info they grow around 5 inches in diameter I think.