My goldfish is missing scales- help!?

I am the proud new owner of two shubunkin goldfishes. I've had them for almost three days, and one of them has a problem- missing scales. A bunch. The specifics are this: two fish, sixteen gallon tank. Same species, same pet store, where they lived in the same tank. I have an appropriate filter, my tank has... show more I am the proud new owner of two shubunkin goldfishes. I've had them for almost three days, and one of them has a problem- missing scales. A bunch.

The specifics are this: two fish, sixteen gallon tank. Same species, same pet store, where they lived in the same tank. I have an appropriate filter, my tank has been established for a month, and my water is safe- no bad chemicals or ammonia problems, I had it tested at the pet store.

As far as behavior, I haven't seen him rubbing against anything (and I watch those fish like they were a TV). Out of the two he is the healthier, more active one- eating healthy amounts, mostly hangs out by the surface of the tank, fins are not clamped. Overall, he behaves exactly the way he's expected to, according to what I've read and what the pet store told me. The only oddity is that he picks up rocks and carries them around... apparently just for fun, he drops them wherever. And he sucks at the rocks and structures, which makes me wonder if he's searching for missed fish flakes? Malnourished?

The affliction was easy to overlook- he's all white except for a single orange dot on his head. I just happened to notice that he looked kinda off-color on one side. Upon closer inspection, I noticed that his right side is almost completely bald. He had a couple little patches of white fuzziness, but not the classic-looking fungus, and I thought it might be some sort of natural coating protecting the worst of the bald spots?

Anyone who knows anything about fish, please let me know. Missing scales, minute coating, weird "hungry" act. Is it likely he had this before he got here, or is three days enough time for half a fish's scales to fall out (all on the same side)? Do I need to worry, or will this set itself right? What can I do to fix this? Is there something wrong with my tank?

Many thanks.
4 answers 4