I just found a purple lobster hitchiking in a piece of LR. I thought it was a mantis, so I dipped the rock in some RO. Turns out, its a purple lobster. I'll try to get a picture of it, if I ever see the bugger again.
I have one of these called a debelius reef lobster. Beautiful but always hiding. How big is yours and have you started losing animals? I have lost (as in can not find) a goby and a maroon starfish. just disappeared. This morning I found my brittle star with 2 legs that looked like they had been chewed on. I am suspecting my lobster as I can not figure anything else.