Help...tangs are sick!

[shinekjl]

I am at a lost...I have a salfin tang and a yellow tang. I have had them for almost a year. All of a sudden they have become sick. Their eyes are cloudy and the yellow's fins are rottening as well. I have treated them with marcyn and marcyn 2. They seem to get better then they are back to the same way. I have also treated them in my med tank with copper. I am at wits end. All of my levels are normal and I do regular water changes with R/O All of my corals are doing great also. Today I have noticed that neither of them are eating. I feed them seaweed, flakes and/or frozen shrimp. I alt every day. I have a protein skimmer and a cansiter on a 75. I hope someone can give a hand! Thanks

 

[lion_crazz]

Well, the first thing that I notice is that both tangs are in the 75. Even though some have been able to survive in this size of a tank, it really is too small of a tank for a tang. This may be why they are suffering after you having them for so long.
Could you also go ahead and post your exact water levels so that we know that your normal and our normal is the same?
What have you been feeding these fish for a year, also? Do you use any vitamins?
What else is in the tank with them?

 

[shinekjl]

I am sorry I forgot to post...my levels are as follows:
nitrates 0
nitrites 0
ammonia 0
Ph 8.2
Ca 450
Salentity 1.024
I water change once a week also.
I alt feed them algea with garlic, frozen shrimp, and flake food. There is live rock, corals, 2 cleaner shrimp, hermit crabs, snails and 3 cleaner clams in the tank. I hope this helps. I know that the tank size is not the best but I rec'd them from my brother before he left for over seas and he also had them in a 75 since they were very little.