I did some digging and it looks like I've owned this fish for ~4 years, and based on the growth rate I've seen with it it was probably 1-2 years old when purchased. Any animal that lives long enough will eventually develop some sort of cancer.
There is a maybe 1/8" diameter bumpy red lump growing where the other pectoral fin connects to the body. Looks kind of like a tiny raspberry. So it's got clearish lumps on the dorsal, bumpy red lump on a pectoral, the less clear lump on the ventral, and it's fatter than it should be. I would love for it to be Lymphocystis and while what's going on looks very similar to it the lumps don't look quite right to me to match that diagnosis. That was my first thought too. Treatment for Lymphocystis and tumors is exactly the same though, clean water and hope, so if i'm wrong and it is Lymphocystis i'm still doing the correct thing.
Nothing else in the tank is displaying any symptoms, it's still eating and swimming around like normal, the lumps don't seem to be growing very fast or much at all. I suspect that once it starts acting different to the point where I can catch it is roughly the point where I should euth it.
It has been exposed to a LOT of iron, I have an 8"x8" patch of Red Crypt that's about 16" tall and a bunch of Hygrophilia polysperma var. "Sunset" in the tank so I dose iron when I fertilize and have been for years. I dose Flourish Excel, Flourish, Flourish Trace, Flourish Iron, Flourish Potassium, and Blackwater Extract but generally only once every month or so except for the Excel and Blackwater which are about every week. It's also been exposed to aquarium salt and Melafix a couple of times. It's been exposed to a lot of random crap is what i'm saying.
There doesn't seem to be any symptoms of swim bladder issues so that can pretty much be ruled out as a cause for the fatness.
My phone camera is ancient, i'm not great at pictures, and I need to clean up the plants and glass but this is the 29g it lives in. You can see how and why it is impossible to catch. It magically disappears into the giant patch of Anubias nana or the Red Crypt or ???. It is very very fast and there are countless hiding spots where no net can go.
Thanks everyone!
Honestly it could also be fat because I sold 400 Malaysian Trumpet snails a couple of months ago resulting in a LOT more food for it to eat. I know fish can get fat and I know it's been gorging itself recently. I have cut down on feeding but probably not enough to equal out removing 400 .5" to 1.5" MTS.
