sick sohal, help asap!!

[naesco]

What are the water test results
Are there any spots, redness, white fluff or fin degeneration
When is the last time you saw it eating anything

[dawen]

ammonia is 0, ph at 8.1 phosphate 0 nitrite 0 nitrate 20

the last time i seen it eating was just last night, i do feed them with mysis also, the body some of the lines has disappear, there is no fluffy or redness

[naesco]

Sorry I could not reply earlier.
You need to set up a QT. Get ahold of of a medication that contains neomycin. Most of the meds out there are useless. Follow the directions carefully.
Soak small amounts of different foods in garlic extract (Garlic Extreme) or fresh garlic juice you make or garlic extract (not garlic juice) you get from a health food store.
Garlic sometimes makes a fish the won't eat, start eating.
I would also stick a bubbler in the QT to ensure there is lots of oxygen
Good luck
BTW your tank is too small to accommodate any acanthurus species tangs.