As always the living things found on live rock weeks after arriving is fascinating to me. I have found a couple that are new to me and was wondering if they are reef safe. The first is a cup coral, it has a brown shell with clear tentacles with white tips and spots. Not very big the shell maybe 1/4" the tentacles extend alomost an inch. The second may be hard to find the exact type so it may be easier to narrow it down. It is a sea urchin, it must have been much smaller when I placed an additional 15# of live rock in tank a few weeks ago or I would have seen it. Now it has a body about the size of a chick pea dark in color with cream color spines just shorter than body diameter. He seems to hide in the day, moon lights gave him away at night. The exact type may be impossible but are there any that are not reef safe?