I saw this morning that I have these small white Octopus looking creatures in my tank, are these critters known to attack Ric's and Yuma's? I have had a few "melt" away here recently
Could it be a mini brittle star? Asterina Star, Aiptasia? Without an image it's hard to speculate, but I doubt an Octopi would feed on your corallimorphs. Lighting that is too intense or water chemistry are the usual suspects. Take a look at the link below and see if you can find your unknown.