(brown) Scopus Tang feeding habbits?

hi guys

just wondering about the feeding habbits of a scopus tang
LFS told me it would eat algie which i have no shortage of but it would appear the tang doesnt like algie all that much.

i woke up the other morning and noticed he had lose of colour on his fins and swiming on his side as if he dint have enough energy to stay upright i knew he was a green eater so i threw some zuchini in the tank and he went nuts for it like he was starving :-/

is there any kind of food thatwuld be better for him to eat i dont want to polute the tank

thnx in advance for any help

 

some people use broccoli or get some nori or seaweed sheets for either fish or people.

 

thnx

should i clear out any excess thats left over or leave it in there for him to chew down on threw the day?