yellow tang doesnt look right

Try feeding him nori, He might not be getting enough food.

This is what happened to my Tang. I gave him away to another reef aquarist after the search ended for my Coral b’s.
It was internal parasite. He would eat but stay thin and because of this he developed red areas. You could try feeding him metrodiazole in light quantity. Feed him soaked foods in Selcon to boost health.

Pineapple, the parasite you are talking about is one that i have heard of before. The tang is noramlly weakened due to improper feeding (not enough vegies) normally. Eventually the fish sucumbs to the parasite leaving red blotches or streaks behind. to cure the fish, improved feeding is needed and higher or better quality vegetable food is recommended.

Mysis,

Diet and water quality should be checked first but this doesn’t always work. That’s way you always have a plan B. My tang had an internal parasite that diet and water quality alone would not cure.

i went through the same thing with my tang when i was just a beginner. I simply bought a lettuce clip and dried sea weed ( you can get this from your local grocery store with the asian foods. Used for wrapping sushi) the Tang loved the dried sea weed. when i stick it in the tank its looks like a kid on a sugar rush. The Tang goes crazy and now he is nice and healthy and well getting fat.

Tang heaven is good along with Nori. http://www.ipsf.com/

I know eBay gets criticism for selling live animals but these algae are on there.

Pineapple, can you tell me the name of the internal parasite that caused this? i have never heard of internal parasites causing red blotches or streaks.

Also if the fish is a recent import it also may show red blotches due to improper water conditions, oftenly a series of water changes to improve water quality will clear it up, along with examining your filtration to make sure that no improvements need to be done for long term stability. And if the condition seems to get worse then you should QT the fish and use antibiotics.