markings

Hey guys, apologies for the long post but I can’t find anything on these white bullseye markings on multiple tangs. I have 2 tanks, both have been running 2 years just about. Mixed reef and the fish are thriving. Parameters are ideal. Recently I purchased a convict tang for my bigger 165 gallon...

Anyone else’s Bicolour Blenny have markings that show up under bluer lights? I was really worried the first night I noticed this but he seems happy and healthy enough!