Backyard Aquaponics
A place to discuss aquaponics

Very slight
1 dead fish as against 100 dead fish



It's not white spot is it ?
Otherwise known as ich.
Seems wrong tho as ich is a warm water disease afaik.

I googled pics of Ich and thought it wasn't, the example pics I found showed many small white spots like a pox, however I'm not really sure now? The water gets very warm through summer here, so could of contracted something then perhaps, I know little to nothing on this currently. it could explain why I see them poking their heads into the wire mesh a little, probably the only part of the tank they can scratch themselves a bit.

Today I gave them all a 6 hour salt bath in 12ppt hopefully. (3.5KG salt in 300L water). I couldn't do it earlier as it takes quite a long time to catch all the buggers. None of them looked distressed at all. I think in advanced cases the skin starts to peal a little, you can't see this when holding a fish out of water though since the skin isn't floating and we are talking very small bits. I then put them back into the main tank and dumped the 300L into the system as well, bring it up to probably close to 2ppt.

Below it a couple of more pics, the first outlines the zones of their bodies that appear to get infected primarily. The second is the best my 6 year old boy could take using my phone. I hope someone can identify it, I feel bad for the poor things and don't want to loose them of course so will do a heavier flush of the system if needed.





Can anyone identify it?

Can you post a picture of your system and the surrounding area?

See if there is sign of improvement in the next day or two. If not, brine them again at 12ppt again; try to leave them in as long as possible whilst being observed for distress, I did my barra for 10-12 hours.

I'd be adding a little more salt to the main FT and bringing that up to 5-6ppt.

What are they eating? How much? How often? Has this increased or reduced since you started getting sick fish?

It seems to be identical to what I've got in my system. It's taken out a few of my cod so far. I'm in Adelaide too.

I salted to 3ppt, and the fish seems to have gotten better, but without a salinity meter, I'm not sure what the salt levels were, with me needing to top up a bit (leaks with me playing around with the tank). So it went for 2-3 weeks without any deaths, then I found a few dead ones on the weekend, so I've dumped in more salt to bring it up a bit.

Makes me wish I never bought the goldfish that carried in the disease.

Somebody correct me if I'm wrong, but the parasite lives in the water, so giving them brine baths will only help as a temporary measure? You've got to keep the system salted until the parasite dies off.

Interesting, did you ever identify your parasite? Also did the goldfish fall sick? I have two goldfish out the back and I do transfer water plants between them sometimes so its possible it came in that way too. In other threads I've seen people say to introduce salt quick and heavy as parasites can adjust to salt levels also, it just takes longer?

I didn't identify them properly, it looked exactly the same as yours. But the treatment is usually the same, add salt. It was working until the salt levels were diluted, I'm just guessing now with the amount of salt I'm adding.

The goldfish still seem fine. Apart from Speckled Jim (a large white spotty fancy goldfish), they haven't been affected with anything.

And yup, quick and heavy with the salt, shock out the parasite.

Another sad installement in this saga, today I found another dead fish. It was one of the larger one which seems to be a pattern for some reason. Oddly this time though is that there wasn't any overt blemishes or parasites I could see leaving me a bit mystified.

Anyway, I have stuck in all in my 300L tank again for another salt bath. This time I'm armed with a cheap ($35) refraction/spectrometer thingy, I've calibrated it to 0 with demineralised water. So far I've put in 7KG of salt into my 300L tank. Yes you read that right, yet its only reading 2.6ppt so far. I stir the salt to ensure its dissolved before adding, so there is not visible crystals left.

So why is the reading so low? Does salt take time to truly dissolve? If so how long?

I also meansured my FT and found it was about .1 ppt even though its had around 7KG of sat (5000L system), What is going on?

One fish in the salt bath started swimming upside down, again a larger one. It seemed to be the only one suffering so I can't tell if it was the salt or was already on that road. To be cautious I diluted the tank by 50% so in theory bringing back down to 12ppt.

I googled around and came to the conclusion that:
A. If there are no crystals visible then the salt is 100% dissolved
B. That my refractometer is rubbish and highly inaccurate.

Still want to hear from others please

Often salt bathing can be a double edged sword. The process of catching and transferring fish can stress and accelerate conditions which push already suffering fish over the edge of recovery.

Salt bathing be fingerlings and crustaceans before introduction is best for prevention rather than cure.

Yes, but once infected choices would seem rather limited.

Yep. Thats my point.

In some cases its better to salt the system, increase aeration (and if possible raise temp) and wait. SP are quite resilient and would cope better with transfer to salt bath but trout I wouldn't bother and treat the system as a whole rather than doing externally unless you have them already in a transferable basket to prevent the process of chasing and catching.

Feels like it takes a life-time to get good at this. I like the basket comment, makes me think about building such a device for the future. It would have to big and cater for 200+ large fingerlings.

I think some of it has to be bad luck too. I'm sure there are people who have been doing it for years without encountering a problem like yours, and if they suddenly did they'd be just as much at a loss as to what is causing it and how to fix it as you are.

It's always possible that even following standard prevention methods (quarantine and salt before adding to system for example) that something like that could happen.

Did you look through that Silver Perch diseases manual I linked? They had autopsy techniques as well as a bunch of photos of diseases and infections and treatments, although most were as you are already doing (salt treatment).

Wishing you the best of luck, I do hope you can get to the bottom of it and have it sorted. It's got to be distressing.

As you haven't yet identified the source of the infection and removing the fish to a hospital tank appears (from a distance) to be beneficial for only a short period of time, I reckon the parasite/virus might be water-borne? You can keep treating your fish in the separate tank but they'll get sick again when you put them back into the infected main system... it might be time to treat the whole system??