Not all invertebrates are "reef safe." Many invertebrates will tear up corals, consume fish and otherwise destroy other tank inhabitants. These invertebrates are some (not all by any means) generally considered by experienced reef tank keepers to be safe for reef tanks.
More: Reef Safe Fish Not all fish are "reef safe." Many fish will tear up corals, consume other fish and invertebrates and otherwise destroy ...
More: Reef Safe Rock & Glass Cleaners do a great job of eating all that algae that's growing on your Live Rock and aquarium walls. Oddly, though, these critters usually won't touch your substrate.
Photo © Sbstew

Comments
i recently added liverock to my saltwater aquarium and i woke up this morning to a little shrimp lookin critter making his way around my tank,,it is Verrrry small, no bigger than a erraser on a pencil, i was wondering, is this thing harmful to a new aquarium?
Wet-Dry filter. The problem is, It filters out the calcium for the corals & you have to keep adding calcium. The cost go up. Also you can’t keep pregnant sea horse’s because when they have the babies, the babies usually go over & down the the wet-dry. So now, I will stay with a closed tank & ender-gravel & live rock.
What is your opinion?
Mike