Good Morning everyone.

Yesterday, I came home from an extended weekend to find my male betta acting strangely. Upon closer inspection I noticed that he's not in the best of health. And as he refuses to stay still when I try to use a flashlight for closer inspection, I'll describe what I saw the best I can.

There is what could be a lump above his gill, and behind the eye, but as he won't stay still I can't be certain. The scales on and around the area are raised and protruding (it really does look like part of a pine cone) but he seems to be breathing normally . His eye is showing no indication of popeye, thankfully. I'm not seeing the white spots typical of ich and he's always had a gold cast to him, so I'm pretty confident that it's not velvet. I have evacuated him into my isolation tank and he seems to be much less stressed without the constant current from the filter. He has also always had an inflamed swim bladder, so I can't confidently say if his abdomen is swelling or not either yet.

I'm running a long established 10 gallon tank, with normal water parameters (0 Nitrates, 0 Nitrites, etc) and zero ammonia at around 78 degrees. I cleaned the tank and did a water change before I left for the weekend and confirmed the water quality when I returned. I recently added a spotted Cory (about two weeks ago) but I properly quarantined him before introducing him to the main tank.

The betta's appetite is normal, but he's lethargic and obviously in some discomfort. Has anyone experienced anything similar that may give me a direction for treatment?

Thanks much in advance!