Backyard Aquaponics
A place to discuss aquaponics

Nothing can run off the pavers into the tank when it rains.

No Dufflight it cannot run into the tanks from the pavers. the only way water can get in is rain or tap.

The rain can oly fall onto the growbeds, there is no collection system.
The tap water comes from the outdoor sink that is only used to clean fish and wash veggies(organic veggies) or from a dedicated station of the retic.

We think its oxygen saturation and i have turned off the air for about 30min, the fish look better. However they have done this before, got sick, some died, got better again.

does anyone know where to get a DO meter or test kit from? preferably on loan

90% water change with water from the tap?? What are the water test results a day or two after the water change?

With heavy metal poisoning it effects their immune response. So they don't die of heavy metal poisoning, they die of just about everything else. So if your fish have fungus, or ulcers or other large lumps (dropsy) then I'd be thinking heavy metals, but if they're just dying for no reason you'd have to look for another cause.

A 90% water change can stress the fish pretty bad if there is a big temperature change, pH change etc.

Who's "we".... how many airstones are you running in what sized tank....

If you're just running a normal "air" pump... at the most you migh be reaching saturation levels... but more likely you're around 10-12 max....

It's not oxygen saturation.... unless you've got the tank boiling so violently... in which case you could be buffeting, bruising, stressing your fish... and/or wearing them out through exhaustion swimming against the tide...

Even then... fish can usually find a "quiet" spot to linger and rest...

It's basically impossible to super-saturate a tank with "air"....

No store purchased veggies washed in the sink.

I would still lean to sabotage, poison of some sort in the water, if this was the case then 100% change would be needed and probably a good clean up, not that I am a trout expert but they seem more susceptible to contaminants and change, much like marron, testing would be expensive and would be far better to start from scratch, the only other thing is blue/green algae which is toxic but have only seen it in waterways and lakes, if not sabotage then someone spraying fruit trees or using fruit fly bait near by, weedicide, or even some lawn fertilizers or the weed and feed containers you can buy, spray can drift a very long way, do you live near a park or reserve, check to see if council has been spraying, from deaths I have seen so far trout don't seem to take much of anything to upset them

Could it be chloramine poising

according to the water corporation chloromine is being used to treat some of the water in WA

with a spike in fish deaths just after a 90% water change this seems a likely cause (if you used tap water)
chloramine is persistant so even if you have had the water in another tank for a couple of months it still may not be safe.

Cant add the PDF from the water corporation but it is here

http://www.watercorporation.com.au/_fil ... _4_pdf.pdf

I got this pamphlet in the mail so I know the water up this way is being treated.

John

No store bought veggies, no fertilizer or chems in the soil or on the plants in the grow beds

No obvious lumps, rot, deformaties etc except possibly pink/red gills. this is why i thought oxygen saturation as with oxygen toxicity in scuba divers the nails and lips go cherry red from engorged red blood cells.

THe air pump is big, the biggest the shop had. I believe 160lpm. the system is 4000lt water. I cleaned the ai filter out a few days ago, just shook the dust off it.

THere is no way any major spray drift could get to my system. I have few neighbours and they all either dont garden at all, or are organic too. It would have to be highly toxic to affect my system from the distance.

I agree the 90% water change was extreme, but with so few fish the amonia levels would be low, so the bacteria should deal with it even after a hit like new water. THe volume is also big enough that it should take days to get to toxic levels

I just checked, one fresh dead fish, but all others looking better. Maybe not Oxygen saturation, but could be air linked?? Dead roach in the air line??

What brand is the air pump?

Well I was told a while back that chlorine could knock out the bacteria, hence it may not deal with the ammonia as well before. Have you done a water test just to be sure?

Without water tests it is hard to tell what is going on.

A 90% water change without pH information could have been bad if the system had a low pH and a 90% change took the pH from say 6 up to 8 that would be a bad enough change to continue knocking out fish already stressed from whatever else was going on, which we don't know without the water test info, this could remain a mystery.

You can get DO tests from an aquarium shop or order one online. I have one that uses a test tube and 3 different re-agent bottles and only takes a couple minutes to do.

I agree that the air itself isn't what is killing the fish though it is possible to bubble the water so much that the fish become exhausted and could therefore be immune-suppressed. This seems to be more of a problem with really small fish that can get swept away with the smallest current though, larger fish can usually find a way to rest.

Going back to DP's construction, noticed heaps of Limestone Blocks, could they have anything to do with it, we have had plenty of rain and wind etc. Pic below

Limestone leaching would show up as a pH change. THat hasn't happened yet. The pH is very stable. Also the limestone is under the growbedsso the rain does not fal onto the limestone then into the ponds. THe rain gets in by falling on the growbeds and returning through the pipes.

I took two fish to the Department of Agriculture fish section today and they are looking at them. They ruled out gill flukes straight away.
I have not fed them at all for 3 days and before that i fed them once in 5 days. I doubt its starvation though. THis should rule out ammonia or nitrate poisoning

No worries DP just trying to eliminate anything, will be an interesting outcome, as all the obvious things are ruled out