Little critters crawling around on my mushrooms?

[algaepad]

Hey guys! I am hoping somebody out there can tell me what these little paramecium looking things are that are very slowly scooting around on my mushrooms. They are approx 1cm in length and width and they are oval in shape. They are not only crawling around on my mushrooms but they are also on the tentacles of my frogspawn and a couple of other corals. What are these little critters? Anything to be concerned about? They dont seem to bother anything. Sorry I dont have a pic.
Thanks in advance!

 

[attml]

Most likely normal infauna (Isopods, copods) which are a normal and benificial part of a reef sytem.