Poor Flippy, you & all your fish. It sounds like a good treatment plan. Good luck! They can be hard to eliminate, in both ways. I think epsom salts are a good idea, the dead worms can be hard to poop out especially for smaller fish.
I've only had it once (knock on wood) in wild gobies. I used levamisole or flubendazole but lost 4 of 5 (sniffle). I knew the only female didn't look great but took a chance I could fatten her up...& then I saw the worms after a week or 2 in QT. I also told the guy I got them from & he offered fenbendazole but I had what I thought were better meds since neither has to be in food. I think they may have had them for a while...
I forget the lifecycle but I think they lay eggs when sticking out of the vent to be eaten & infecting other fish. I know you have your hands full but try to vacuum as much as you can...assuming the eggs sink. It's been 10 years so I'm foggy on details.
On a happier note, your corys look great!
Apparently the life cycle:
Lay eggs
Eggs eaten by cyclops or other crustaceans
Fish eat cyclops
Young worms mature in fish to repeat cycle.
I'm dosing the food. Best method for internal parasites.
1/8 teaspoon of 22.2% fenbendozole (Panacur C) dissolved in 1 tablespoon distilled water, food left to soak in this for 1 hour before feeding. Feed 3x a week.
Doing Epsom soaked food for the worm expelling, to prevent worms from getting stuck inside the fish. 1 tablespoon Epsom to 500mL of distilled water, and use just what I need to soak their daily food until there's no excess water and then feed.
And also garlic powder to mask the bad taste/smell.
And I've got some antibiotic food I plan to keep on hand juuuust in case I see signs after of secondary internal infection as a result of retained worms.
Absolutely no fasting days either, I want to keep their gut moving so nothing stays trapped.
And yeah, good vacuuming, filter cleaning, whole nine yards.
Lots of work, but I'd rather my fish be alive and this not grow into a bigger problem. I don't know if it could have spread among my tanks thanks to shared water changing gear, so that's why all 7 tanks are under the same regime. I'm not messing around with camallanus.
My understanding as well is meds like prazi or other external meds arent super effective with camallanus. Not like those are super easy for me to get though either.
Flippy is absolutely the only fish I've seen these worms in, but at same time I'm wary of the male that's in my rainbowfish tank who came with Flippy. He's not as outgoing as Flippy so he's hard to get a good check on. But, still. General rule with internal parasites is if one has it, assume they all do or will get.
No idea if they have been hidden silently in my tanks this whole time or if they came in with Flippy, end of the day it doesn't matter as long as they're treated.
Because of the illness in my rainbow tank, I've been doing my water changes in a particular order so that the water change gear doesn't infect other tanks from that tank.
Order I change the water:
1 the south American
2 the 135 goldfish
3 the 10g nano
4 the 5g betta
5 the anubias 55g
6 the 20g blackwater
7 the rainbow 55
And then my gear is set away to dry for the week between use.