Backyard Aquaponics
A place to discuss aquaponics

Is there any one who can tell me what happen to my silver perch, they had been in their tank and pond for approx. 4 weeks, when they just started to die, they all developed a clear mucus coating and there skin went blotchy, with in a week of these signs occurring one buy one they started to shows symptoms and then die, i think I have two left out of forty odd and don't hold much hope for them, any advise on what caused it and what I could have done to stop it once the symptoms appeared, i tried salting the water but it may have been to late or not enough

Water temperate and/or water quality are most likely the cause...

Where are you located... how big were the fish... and what were your water test readings?

All my water test and temperature were fine, they ranged between 50 - 100mm long, located Newcastle, yabbies are doing fine

Unless you give us a bit more information there's no way anyone could possibly diagnose a reason for the fish deaths

- Did you cycle the system before adding the fish?... or cycle with fish?... and if so, what levels did your Amm and Nitrites get too?
- If you cycled first, what were the water test readings (Ammonia, Nitrite, pH & min/max temps) when the fish went in?... and afterwards?
- What are your water test readings now?
- How many litres of gravel in your GB?... what are the GB inside dimensions (LxWxD)?... and what level does it flood too?
- Is the system constant flood, timed flood & drain, or siphoned F&D?... what are the flood and drain cycle times?
- Other than the water pump, do you have supplementary aeration?

Sounds like Freshwater White Spot disease. Sometimes referred to as Ich. It usually happens when you transfer an infected fish into a different system but can also be caused by poor water quality. It is VERY hard to get rid of, usually killing the entire lot of fish unless you treat it quickly. You may want to do some research on it as now that it is in your system, there are chemical treatments but I don't know what effect they will have on your growbeds and vegetables. I wouldn't add any more fish until you figure it out, and do NOT transfer anything from this system to another.

With a "mucous coating" and "blotchy skin"... it's not "Ich"... much more likely Saprolegnia... and hard to treat...

"Ich" is relatively easy to treat before fatalities...

A picture of one of the live infected fish would be helpful if you can get one.

I cycled the system for approx. 4 weeks or so while I got my bell syphons to work properly, Ammonia and nitrate levels where and are still fine, water temp is around 21-22 degs. Celsius, water still test fine even after al fish have died, yabbies are doing fine, PH is in the high seven's, there is just over 600 ltrs of grow bed gravel which flood to approx. 550 ltrs. they are approx. 1.0 x 1.0 x 0.3m each, they work on a bell syphon system which fils and drain approx. on a 15-20 minute cycle, there are plants in the system to supply additional aeration, does this help any

Trege, cycling refers to the time taken to establish the bacteria colony, this is determined by tracking the Ammonia and Nitrite levels... once both have peaked and dropped to 0.0 the system is deemed "cycled"

So did you cycle with, or without fish?... If you cycled with fish, what did your Amm and Nitrite levels get to during cycling?

If you cycled without fish, using another Ammonia source, did the Amm and Nitrite levels spike after the fish were added?... if so, what did they get to?

Just saying the levels were and are currently fine tells us nothing and doesn't enable us to help you.

As jrl91rs mentioned, a picture of the affected fish would help, as would a few pictures of your system, including a picture of the water in the FT.

Cheers.

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nope - click 'img'
looks like this for external pics


for attaching a picture down the bottom - you'll see 'choose file' - then 'add the file' then 'submit'

I finally managed to get a photo to attach, cab any tell what is wrong by this photo

As Rupe said most likely Saprolegnia. It got all my SP too after they got ich... nothing you can do now.

It tends to only get weakened fish. For example my SP were in the same recirculating water as my trout, just in separate tanks, and I haven't lost a single trout... other than to my frying pan and stomach. I also had 5 goldfish in the same tank as the SP, and they got ich, but not Saprolegnia. They all survived.

Salt to 3ppt and they should be ok in future... I'll need to think of a way to do strawberries while also having salt in my system...

Of my 25 SP I bought this time last year I lost them all to ich and Saprolegnia.