Oranda has...blisters?

Question
Hi, I was just noticing yesterday while doing a water change that my very large oranda seems to have what looks like blisters on one side of his head.  It's on his cap.  The ammonia and nitrite levels are both 0.  Nitrate is always high (can't seem to ever bring it down even with Nitrate sponge in the filter box).  Other fish seem happy. And he doesn't seem sick.  Should I be worried?  

Oh, by the way, I have a 55 gal tank with an Emperor 400.  I only have three fish (my oranda named Mittens, my black moore named Hammy and a plecostamus named Pleco) so I know the tank isn't overcrowded.

Celeste

Answer
Hi Celeste,
From what you are describing, it sounds like fish pox. Fish pox usually only causes bumps  and doesn't require any medication. Since your fish doesn't seem to be sick otherwise, then it is probably only the fish pox. It is common in goldfish and koi. When they are kept in ponds it usually goes away when it warms up. Just be sure to observe it just in case something else develops. It is hard to diagnose illnesses in fish so it is always best to observe them for a while just to be sure. It will probably go away. It shouln't cause any other problems other than just looking bumpy.
Keep an eye on those nitrates. They can cause some problems with your fish if it gets too high. The best way to control them is to do frequent water changes. Even if you have to do them twice a week. It is better to do frequent water changes especially with goldfish than to  not do them and have the fish get really sick. Since they are really dirty fish they will pollute the water quicker than most fish and so will the pleco. I know the pleco that I have produces alot of poop and I always have to clean the tank at least twice a week. One thing that does help some with the water conditions is using Amquel Plus or Prime water conditioner.  They also help with ammonia, nitrites and nitrates along with also neutralizing chlorine and chloramine. You might want to try some to help with the nitrate problem. Also, one other thing I wanted to mention is about the pleco. I put one in the tank with my goldfish and thought things would be ok. Well, he decided that he wanted to eat the slime coating on my gold fish. It really leaves a bad red spot which can really cause an infection. They can also try to do this when the light go out at night and you can't see them. Just thought I would mention this just in case it ever happens to you.
Hope this helps,
Karen