White fungal spots on sailfin pleco- used aquarium salt in 500l tank looking for advice

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GermanFishKeeper

Feeder Fish
MFK Member
Oct 27, 2025
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Schleswig-Holstein
Hi everyone,
I have a 500 L freshwater tank with one sailfin pleco (Pterygoplichthys gibbiceps), several cuckoo catfish (Synodontis), and bristlenose plecos (Ancistrus).

Two days ago i bought a sailfin pleco from a friend who kept him 20years in a 200l tank, now after the transport the sailfin pleco developed thin, white, cotton-like streaks on its skin – looks like an early fungal infection.
Following advice from my local aquarium shop, I added 500 g of aquarium salt (≈ 1 g/L) to the tank.
The fish seem fine so far – normal activity, breathing, he doesn't eat.

I now plan to keep things calm, observe for two days, and then do a 50% water change to bring the salt level down to around 0.5 g/L.
If the fungus gets worse, I’ll consider treating with eSHa 2000 or Sera Mycopur, which are said to be catfish-safe.

Does this sound like a good plan?
Any experiences or tips with using salt or mild treatments for plecos would be greatly appreciated.
I just want to make sure I’m not stressing the fish too much.

Thanks a lot!
 
I would stick with the salt for a few more days.

It's hard to see on the pictures. Are you sure it's fungus and not just loose parts of the slime coat?
 
Tannins are anti-fungal und safe for plecos (and every other fish I know off). They also help against bacterial infections, some parasites and benefit fish health overall.

If you live in germany, you can get them very fast by adding dried beech leaves (Rotbuche). Ideally find some fallen tree or branch and collect the twicks that have dried firm leaves on them. Throw them in your tank and wait, after 2-3 days your water will turn deep brown-red. Your pleco might eat them but thats totally fine, you just need to clean your filter more often if he does due to him creating more waste.
 
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