Can you tell me if this is something I should be worried about?

[mrangel]

I got two clowns and one yellow tang. My clown wasn't eating, but now seems to be doing better.
I noticed that my tang hs a little brownish spot that appeared yesterday. I hadn't noticed it before. He seems to be eating fine. I have rocks in my tank and I think he just rubbed up against it. He is eating fine. Although, he is shy and hides in the cave.
Can you please look at this and tell me if it looks like some sort of disease.
Its on the top fin. I little brown spot. I hope you can see it.

 

[beth]

That fish is way too skinny and the color is somewhat pale! I see the spot and it could be a sign of problems. Can you give some details about your tank, water readings, age of tank, how long you've had tang and what you are feeding him.

 

[mrangel]

I got the tank in December and it's been running ever since Dec 26th.
My water readings are ph 8.2, Nitrite 0, Nitrate > 20, Ammonia, 0. My water temperature is 78 degrees, Salinity is 1.021
I feed them 2x a day, O.S.I. Marine flakes and Spirulina. I also put some Nori Algae clips. He seems to be eating fine. He is a baby and I've had him for one week.
What do you think?
I took the picture yesterday and now it looks like it is spreading.
What other types of food can I try and give him?
Marguerite