wrote in message oups.com...
Recently I was looking into my 'fuge pondering whether my inability to
keep macro alive was a good thing or a bad thing, when I noticed
hundreds of tiny arms waving at me... some brittle stars must have
spawned as I've got hundreds of tiny baby ones.
Thing is, I'd like to move some into the main aquarium, and possibly
raise some and sell them...

I would rather bet these are tiny adult britle stars - common in the
refugiums - they never grow into a show-size stars available in stores.
The biggest I was able to see in my tank were 1" arm tip to arm tip.
Consider them rather a part of your cleaning/janitorial crew.