I think it's a background. Looks like you only have about 3 pieces of LR in there probably need more if you want to keep more than one fish. Also get rid of that background and put up a blue one or paint the back of your tank.
1st i see 6 pieces of lr. they total 25 lbs. i know it is too little, but the rock is expensive.
I realized i took the pics right before i got the fish, and i was too busy afterwards to put it up.
Lastly it is my backround that looks like coral, but i dont see what is wrong with it.
ill try to remmember to get a few mex turbos, but when i added my clowns i also added some really big snails-unsure species. and i cleaned some algea myself.