Backyard Aquaponics
A place to discuss aquaponics

I'm afraid that I am not much help to you as I have never had any fungus issues with fish on the farm so have no experience in dealing with it. All of my recirc tanks and aquaponics system are run with a salt level of between 2 - 3ppt which inhibits the growth of any fungal spores occurring naturally in the water.

As far as the origins go my references state that fungal spores are present in all freshwaters but will generally only effect fish that have become stressed or have a weakened immune system.
So, the answer to your problem may be why have my fish become stressed??

Although you have had no problems with trout over the past 3 years you have to remember that this year you have basically started again from scratch given that you put a new liner in the pond and new water you would have had to cycle all over again so perhaps the fish were exposed to high levels of ammonia or nitrite whilst you were away for 2 weeks at work causing them stress. Another common problem I have heard of is when people get others to feed the fish for them whilst away on holidays or work the friends/family have a tendency to overfeed. Any left over feed is a perfect site for fungal spores to proliferate.

As far as a cure goes from all my reading it seems that once saprolegnia takes hold it can be very difficult to eliminate. Those lower salt levels discussed by others may help prevent the spread of it to other fish but I doubt will cure those already affected. Your going to have to give salt baths of 25ppt if you want to get rid of it completely.

+1....

Thanks Gavin , Your right re the liner though I did manage to save about 1/4 of the water so it had a little bit of a head start .
They didnt show any obvious signs of stress , all active and feeding well .
There are a couple of them with the markings and I was going to take them out and put them in and aquarium but do you reckon I can catch the blighters
When you say 25 ppt salt bath , how long would i leave them in it for ?

Ive put 3kg of salt in my 2000 ltr (thanks to Arbe's maths ).

Cheers Al

I hope you tripple checked it - I wouldn't trust my maths.

Salt has been in for a couple of days now , went with 3 kg .

Can anyone suggest how long it might be before i notice a difference if at all ?

The reason I ask is that I've just been for a look and for the life of us we cant see the affected fish now , though I suggested to the wife that a couple of daysd was probably not long enough for the salt to have an impact .

All seems to be good now , we are 10 days into the salt zone and there appears to be no sign of the "affliction" Fish seem happy and are feeding like only Trout can .

Good to hear Prawnz...