swollen nodes?

Where my paradise fish Laddie had fungus on his fin, the fuzz is all gone now and it's starting to grow back. But I'm concerned because there's small lumps or swollen spots on his fin rays, largest right where the fungus was. Looking close I think there are also lumps where the fin joins the body. I'm not sure how to treat this- thinking of isolating him in a small QT and dosing anti-fungal meds, but could well be something else and the fungus was secondary. He is still spry, alert, eager for food- whereas Perry next door looks mororse or ill. (Separation would also let me see if Perry's behavior changes without a competitor next door). Here's photo of Laddie's bad fin:

Good one for comparison-

I'm asking advice on the forum . . .