Backyard Aquaponics
A place to discuss aquaponics

with most/all of the 99 fish dead, it sounds like contamination or disease, as it happened so quickly.
more :hug:s

Thanks Jaymie.

There are about six still alive. All the dead ones look healthy, except they're, erm dead.

Chin up forest, just remember it's a learning curve.

First post I opened this morning Forest..... bummer..... had hoped things might be on the improve.

Like others have said, head up.... getting your water tested by someone sounds like a good idea.... if you have a local vet you can coerce, then maybe keep one of the fish and see if he'll do a post mortem on it?

Sorry to hear about your losses Forest. It all seems a bit strange to me. I am certainly not an aquarium expert, but I would have thought that if it was simply DO deprivation, that once the DO was provided again the losses would have been minimised - though then again, applying logic to the situation long term oxygen deprivation would cause brain damage and organ damage I suppose.

At the moment I am still using town water for my system top ups (neutralised of course). I have two rainwater tanks here waiting for me to instal them, so am looking forward to being able to use this water instead. What does worry me about this though is the potential to introduce toxins into the system because of naties having settled on the roof (from car fumes, spray drift or anything else) and then got washed into the tank. Would use of some sort of filtation be a sensible option I wonder. Forest - do you filter your rainwater in an way?

Ouch... sorry Forest..

Yes, initial thoughts would definately lean towards DO, but if it was DO then the remaining fish would have picked up when you started pumping in the morning, there is no way that they would have kept dying off during the day when oxygen was being added..

The only real possibility I see is contamination of some type.. Which could have come from anywhere.. I killed a large marine aquarium full of fish within only a couple of hours by dipping my contaminated hand in the water once.. It could be over drift of spray, or it could be something on hands that have been put into the water, or something in the top up water.. Which doesnlt narrow things down much.. Have you or H been using any anti fungal/bacterial treatments lately, putting anything different on your hands?

I hope this doesn;t put you off the whole idea Forest, it is an unusual thing to happen, and I think of all the people on the board this is only the second time there has been a mass death for an unknown/possible contamination reason...

So sorry for the losses, Forest. Hang in there.

I also am thinking contamination rather than DO issues. I would have expected more gulping at the surface for DO. Also, the DO problem should have started to resolve as some of the fish stopped using oxygen -- errr -- died. I'd be looking very carefully for sources of contamination, and before you re-stock, throw some goldies in to test the water for a couple of weeks.

yeah, really sorry to hear this forest.
i have to concur that although do may have weakened them , i doubt it was what killed them. only a complete water test can clear this one up imho. best of luck and hang in there

thanks everyone. It won't put me off, joel, but I intend to do a lot of reading before we get some new fish. There are four fish left now. I don't know if they'll survive or not. They seem healthy enough, but who knows.

We don't use any anti-bacterial or fungal things here. We have no poisons, we use pure soap, often made here. We have a wall of rainforest and a creek at the back, no neighbours at the front but neighbours on both sides. One lot of neighbours were away, the others work all day and I haven't seen them for yonks. They were the ones who came in to tell us they were spraying their roof a few weeks ago, so I doubt they would have sprayed anything around without telling us.

We're talking about dissolved oxygen and I'm guessing that it would be built up over a matter of hours, if not days, to the desired level. I doubt just adding oxygen to water would instantly increase the dissolved oxygen water level. Does anyone know for sure? I found this snippet:

As dissolved oxygen levels in water drop below 5.0 mg/l, aquatic life is put under stress. The lower the concentration, the greater the stress. Oxygen levels that remain below 1-2 mg/l for a few hours can result in large fish kills.

I once had a pump blow on me and arrived home to find a few fish that had jumped ship onto the ground, and the rest were gasping for breath at the surface.. I grabbed the hose and squirted water in a hard jet into the tank, the jet going deep into the water creating lots of bubbles. The fish picked up very quickly after only a few minutes of doing this and they were fine..

My other system when the dog knocked the power cord out of the wall during the night, I awoke to find all the black bream dead on the bottom, a couple of silver perch looked like they might die, and the rest were all gulping at the surface. I plugged the pump back in, started pumping, and did a similar thing with the hose for a few minutes.. Within an hour or two the rest of the fish were fine and there were no more deaths..

This is why I'm leaning towards some form of contamination, because any problems I've had with low DO have been fixed and the fish have been fine shortly afterwards. Where as yours was a slow gradual thing over many many hours...

hmmm, maybe I'd better rethink how oxygen is incorporated into water. It really is a mystery, isn't it. I haven't considered contamination because I thought that once the water was contaminated with anything, that all the fish would die within a short period of time.

I think what happened to you WAS a short period of time... If you had you pump off at night for this long, why did this just suddenly happen? It is a bit strange. If lack of o2 was an issue then you should have lost fish gradually at night when the O2 was exhausted. Plus the fish are quite small, I can't imagine with such a low stocking density the O2 was the culprit....

tim, the aquarium man told us the density of our fish was quite high.

I thought that as the pump and aerators were off for about 8 hours that the fish built up problems overnight but these went once the oxygen was back the next morning. Maybe, after two weeks of that, their little bodies couldn't handle it any more. We have three fish left now and they look fairly healthy. But I wouldn't be surprised to find them belly up tomorrow morning. BTW, we put some in a separate container with fresh water but they also died.

We are going to see if we can get the water analysed.

Oh, I meant to add that I really appreciate everyone's thoughts on this disaster. We are still staunch converts to AP and still think we can get a reasonable system running to supply our protein needs in our sustainable backyard.

Word just in from the backyard. (breaking news lol ) H just counted 8 fish still alive.