Bolivian Ram always sitting, has shrunken belly, had red swollen anus few days ago

[fanyfin]

Does my Bolivian Ram have some parasite or something? It's been just sitting on the gravel for the last few days and today I saw that its belly has really shrunk inwards.

About 5-6 days ago, I saw that its anus area was a bit red and swollen. I thought it was just something I hadn't noticed before and so should be normal so I ignored it. But then, 3-4 days ago, I saw that it was just sitting on the substrate and not moving as usual. Again I thought that was normal because Bolivian Rams are usually quite shy and don't move around a lot anyway and so stay or sit still often. Today I see that its belly has really shrunken inwards and it's still sitting on the substrate and not moving much unless it feels really threatened. Definitely something is going, probably some parasite, so should I quarantine it and treat it?

I have Fritz ParaCleanse which is made up of Metronidazole and Praziquantel. Should I use that or something else?

Also, should I treat the whole tank (all fish - in case it's contagious?) or just this fish alone in a quarantine tank?

Please help! Thank you.

Water parameters stable - temperature 80 F, 0 ammonia and nitrite, Nitrate kept at mostly 20 ppm or less by doing water changes.

 

[Autumnsky]

It sound like a possible infection of Camallanus worm. Can you see if there are any tiny red worms in the anal vent?

 

[Autumnsky]

Says it does not treat round worms or nematodes.

https://fritzaquatics.com/products/fritz-paracleanse

There are several main medications which work for deworming. I do not personally know which one is best, but would need to look it up.

fenbendazole
levamisole
praziquantel

I do know Fenbendazole will work on worms without the need to eat the medication, absorb into the skin.

But, it of course it depends on which worm has infested it, perhaps one works better than then the other for a particular one.