Cardinal tetra with white "thing" on fin

[Kwakatoo]

I have had this fish for 3 weeks.. He's been isolated in a quarantine tank for two of those weeks now.

I thought he had fungus, as it seems to be fuzz. So I treated with Myxazin;
Active ingredients are:
Malachite Green 0.17% w/v.
Formaldehyde 0.24% w/v.
Acriflavine 0.11% w/v.

He's started eating and swimming better,mane spa side from this white thing, seems a lot better.

But what's this thing??

 

[Matt68005]

No clue. Hard to tell from the pictures.

 

[Kwakatoo]

Very hard to photograph. But it's not fuzzy, it's almost vein like but white in appearance. Starting to wonder if it's a parasite, but it's not quite on the body, it's more on the fin. I wish I could catch the fish and swipe the thing off... That's how annoying this is getting! Lol

 

[Kwakatoo]

Maybe it's excess slime coat stuck on the fin as a result of the recent fungus? Anyone?

 

[Kwakatoo]

Ok I've figured it I think. I netted the guy and had a close inspection, it's very much fungal. So I'll clean up the tanka bit, keep meds running and add some harder water.. Gradually.

Been using really soft rainwater from a outdoor tank with some tannins. Reckon if I start adding some treated tap water it'll bring more minerals to the party.