so i was just looking at my tank checking out my corals and everything and i see this on one of the plugs for my zoas. I dont know what the heck it is.
sorry about the tilt on the photo. Just want to know if it is harmful to the tank or if i can just let it be. Where i pulled it off the plug where its body came into contact with it let behind a weird residue.
Its right on the edge of the plug. any ideas of what this could be would be much appreciated.
they zip around

