Just discovered this muscle

[PeterEde]

Doing some cleaning and found it on a bag of purigen.
Must be about 1 month old

 

[JGT]

I have several embedded in my live rock. Been there for a couple years. They will survive if they get some sort of food. I dose phyto so I think that’s what they been living off of.

 

[DaJMasta]

They can often survive off particulate foods too, and will get up and move if they're not satisfied with their place - probably how it got to your purigen bag haha.

I would also guess that's older than a month, not 100% on growth rate of young ones, but I'd expect fingernail or smaller after settling and that looks bigger.

 

[G Santana]

Did you find a jar of marinara sauce too lol
That's pretty cool!!!