Sick Platy

Hi, my platy seems to have a white gel-like mass (not red or inflammed) sticking out of its anus. Other tank mates include two small juvenile angelfish. I had been treating the tank once a week for the past two weeks with prazipro, as the angelfish were not eating. Now they are eating. The other day after doing a water change I noticed a couple small (barely wiggling) nematodes in the water column. I'm not sure if they are parasitic or not, or if they are camallanus. Fortunately I have some levamisole on hand and dosed the tank last night after I had done 3 25% water changes (with vacuum gravel) during the day. Any thoughts on anything else I could do? The platy ate yesterday morning, but not last night or this morning. The last time (also the first time) I used levamisole my fish didn't eat for a day.

An update: Yesterday I was getting concerned and considered euthanizing. The white jelly-like mass grew in size to the size of a pea, and thought I may be too late. However, although she was hiding, her fins were not clamped so I decided to let her be through the night. This morning the mass is gone, now a long strand of white stringy poo. She is now swimming around a bit. I think the levamisole is working, camallanus or not.

Yeah when I removed the "jelly ball" that she finally passed I could see some dead worms in there. she's doing much better. I'll probably retreat 3 weeks after the first dose to kill off any surviving eggs that hatch. I see a ton of them in another tank (bare bottom so it's really easy to see them), so it looks like I'm gonna need to treat all of my tanks just to be safe. Looks like I should now get back into the habit of sterilizing all my buckets/cleaning equipment after cleaning each tank to prevent cross contamination.