Backyard Aquaponics
A place to discuss aquaponics

My guess is http://goldfish2care4.com/goldfish-diseases/cotton-wool.html

Any body had issues with this before and any tips.... got them out the main system now (effected fish) in a hospital tank.

Tried treating with antifungal drops from fish store but not much results after one week. Now im salting the hospital tank.

we live in cold part of world Southern Chile (currently water is at 10 celsius or 50 fahrenheit) in the main system the hospital tank is now fluctuating quite a bit more because its a small tank.

It does look like a fungal disease and it looks like it's spread to more than one fish. I'd look into salt treatment of the fish using a dip in another tank with a higher salt concentration. I'll also suggest adding one part per thousand of salt to the main fish tank to help the fish with stress and help them build a slime layer that helps prevent infections like this. Lastly I'm going to suggest that you look into getting a UV sterilizer which will help reduce the number of infectious fungal spores in the water You won't have to run it all the time, just when you need to get a handle on a disease like this or if you want to reduce the amount of algae in the tank.

I like the idea of the UV to add to the system to handel further spores, not seen to many run them with aquaponics. Looked over that, def get one next visit to the pet shop.

I've just been running with 2 tablespoons of sea salt in the hospital tank, with daily water change. Been trying not to stress them out to much, with the dips. But if no improvement happens next few days I'll start with that as well.