Blue tang with marks in his head

[Luisreefmexico]

Good Morning.
I have has this blue tang for some time, at first when he was younger I thought these marks were his nostrils but now I see them quite strange, does anyone know if this is normal?
I have more tangs and this is the only one that has this kind of marks, I also have to say that it is the most nervous fish I have, any Other or mi tangs are not shy but this is very very shy. As soon as someone approaches the fish tank it hides, will I have to change something of his diet? Or is normal ?
I feed them nori algae and pellets every day

 

[Fish Think Pink]

Good Morning.
I have has this blue tang for some time, at first when he was younger I thought these marks were his nostrils but now I see them quite strange, does anyone know if this is normal?
I have more tangs and this is the only one that has this kind of marks, I also have to say that it is the most nervous fish I have, any Other or mi tangs are not shy but this is very very shy. As soon as someone approaches the fish tank it hides, will I have to change something of his diet? Or is normal ?
I feed them nori algae and pellets every day

I grow Red Ogo in my refugium as tang snack.

Red Ogo

At AlgaeBarn we treat, quarantine and inspect all of our CleanMacro™ Live macroalgae. Bright red and burgundy, with sharp and pointy fronds, Red Ogo adds color to any tank or refugium. It is also makes a healthy live seaweed food for herbivorous fishes. See below for more information.

www.algaebarn.com

 

[Coralreefer1]

Looks like Lateral Line Disease/ Hole in the Head.

 

[vetteguy53081]

Head and Lateral Line Erosion (HLLE) is a common condition seen in marine fish kept in public and home aquariums. Symptoms are pitting on the head and deterioration of skin and scales along the lateral line. The most common fish to show the condition are tangs (surgeon fish), butterfly fish, and marine angelfish, but I have also seen the condition in other fish including clownfish. Head and Lateral Line Erosion leaves open wounds and hinders the immune system of the fish. Combining HLLE and poor water quality can be a fatal one-two punch for your fish. HLLE Theory is Poor Diet and it is believed that nutritional deficiencies are a leading cause of Head and Lateral Line Erosion.
I have found that by simply stepping up on maintenance and water quality and feeding nutritious foods can greatly improve the effect you are seeing.
other causes are stray voltage, running carbon, and copper exposure.

Feed at MINIMUM:
Spirulina brine shrimp
Formula 2 flake and frozen
mysis shrimp
small plankton
Nori seaweed basted with garlic extract
Hikari mega veggie diet
Hikari marine cuisine
LRS Herbivore diet

ADD SELCON VITAMINS TO THE FOODS 2-3X PER WEEK AND GARLIC EXTRACT ON ALTERNATING DAYS FOR IMMUNITY HEALTH AND OVERALL STAMINA.