Raphael has a lump!

[TigerLily]

I just got back home after being out of town for almost two weeks. My brother had been looking after my bettas using the instructions I left him, which covered all of the basics.

While I was feeding Raphael last night after getting home, I noticed that he has a strange dark area on one side of his body, about halfway down his side. In addition to being abnormally dark, that area is also raised and appears very lump-like. It's about the size of a dry pellet.
The discoloration and the bump are only on one side of his body, and otherwise, he appears to be perfectly fine. He doesn't look bloated. He's eating and swimming normally.

My brother assures me that he did not overfeed the fish, and that he stuck to my guide lines the entire time I was gone.

Raphael's five gallon tank is kept at a stable 78F, fully cycled with live plants and currently shared only with one ghost shrimp. He gets 3 pellets at each meal, morning and night. Does anyone know what this lump might be? I had planned to divide this tank to house my new veiltail as well, but I don't want to risk the new guy if this is some kind of disease.

[BettaKeeper]

Possibly a tumor?

Could you maybe post a picture?

[TigerLily]

I'll try to get a clear picture of it if I can.

[BettaKeeper]

Sounds good.

[TigerLily]

I haven't been able to get a picture that clearly shows the lump, but it's still there and I haven't seen any change with it.

Would I be safe to go ahead with my plans to divide the tank? Or should I continue waiting? I'm not quite sure what I should do.

[BettaKeeper]

If it's infectious then it would most likely transfer to the other fish, I'd just wait until the lump is gone. I'm not sure how to deal with the lump though, I'd need to see it.

[TigerLily]

All right, to get an image of it I had to try something different. None of the pictures I took were clear enough to see it, so I tried taking video of him under a flashlight, and then took a still shot from the video.

It's visible in this still shot, however because he was under a flashlight, the color is off. The lump is actually a darker coloration than the rest of his body. There are still no other lumps and he is still eating and swimming normally.

[TigerLily]

Ideas, anyone?

[BettaKeeper]

Looks like a tumor or a parasitic cyst. I'm not familiar with medicines for those though.

[TigerLily]

It doesn't seem to be bothering him, as I've said, although I have noticed what appears to be early fin rot and have started him on a daily salt bath to clear that up. The fin rot isn't something I'm worried about. Salt baths and clean water should take care of that. But, assuming the lump doesn't go away, I wonder how long I should wait before dividing the tank.
Leonardo has been waiting in a 1g critter keeper that I've been using for quarantines. He's all right in there, but I'd hate for it to be long-term.