Black Moor Gold Fish - Bump on Back

Question
QUESTION: Hi,

I have a black moor goldfish that is about two years old.  He has recently
(over the last week) had almost pea-size growth form on his back next to the
fin on the top of his back on the the left side of his fin (if he is looking at
you).  Not sure if he is a he, but we have given him the name Moortimer.

Anyways... what could this bump be and is there something I can do to help
cure it?
ANSWER: Well, I can't tell what it is from what you have put. Please give me more information to work on such as swimming movements, rapid gill movement, ect

---------- FOLLOW-UP ----------

QUESTION: Thanks for the quick reply, hopefully we can get to the bottom of this.

The fish has not acted any different with or without the bump.  
He swims around the tank using his front two fins the most, scooping at the
water quickly.  His large back fin is slightly used with a fluid back and forth
motion.  The large fin on the top of back (which the growth is near) droops to
the side of the bump.

There is no rapid gill movement from what I can tell.  His gills look fine in
color.  He eats once a day in the afternoon and eats his food very quickly.  I
clean the tank once every 3 weeks with a 40% partial water change and
change the carbon filter.  I use the Eclipse Six tank and filtration system.  I
have never changed the Bio Wheel.  I have been told that the Bio Wheel is to
never be changed during the life of the fish.

The bump itself looks like it is under the skin almost the size of a small pea.  
The bump has the same blackish scales covering it that cover the rest of his
body.  There are no other marks found on the fish except for the bump.

Let me know if you need any additional information.

Thanks,
Brent

Answer
It sounds like a tumor. Tumors are untreatable but if the fish isn't suffering or struggling, leave it.
I actually don't know much on Biowheels so I can not tell you if you need to change the wheel. I would ask a place that sells only fish and fish products. They would know more.