16 Month Old Achilles - How to fatten this tang up?

[ca1ore]

Doesn’t look that thin to me. Agree with more nori, also see if it’ll take pellets. Mine eventually did after trying for a few months.

 

[OrionN]

I hang nori clips right at the water surface, enough for the tangs and other grazers to graze on all day. The nori run out late afternoon. Several clips on my 320 gal tank so the Powder blue tang cannot defend all of it. I hang it from above so the snails and other non-fish grazer cannot get to it.