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Catastrophic water change

idris

Member
Joined
3 Jan 2011
Messages
816
Location
Herts
Today I added some fresh water to my tank, and within a couple of hours, all my livestock was dead. (Fish, snails and shrimp.)

Existing 220L tank that's been recently re-commssioned.
Moderate number of plants that have been in for either about a month, or about a fortnight.
New filtration, and all hardscape and glass cleaned with H2O2 or Milton. Anything that had been cleaned with Milton had had several days to dry off and then the tank was well rinsed before it was partly filled with dechlorinated water.
Akadama from previous instalation, probably with a decent culture of good bacteria.

At the weekend I was a little impatient, and as the water chemistry seemed ok (NO2 = 0ppm, NO3 < 20ppm), I transfered my livestock from a smaller tank I'd set up while the big one was recommisioned.
All seemed fine for a few days, and last night all the fish looked healthy and were very active. The world was good.

As the tank had only been about 60% filled, today I added some more water.
I used dechlorinator (which was well within it's expiration date) and heated the water to the same temp as the tank before adding it.

Within a couple of hours all the livestock was dead.
The dead fish were all still well coloured, weren't bloated or emaciated, and showed no external sign of infections.
As everything had been fine for several days, and then everything died very suddenly, I am assuming some sort of toxin, rather than a pathogen.

I tested the water for NO2 and NO3 again. All was fine.
I took samples of both the tank water, and the untreated tap water to the LFS, along with the dead fish. They tested the water and could see nothing that could explain such a catastrophic crash.

So ...
What now?

Obviously I'm reluctant to restock the tank without knowing what the problem is, and even then only very gradually.
Do I drain it and refill from scratch?
Do I leave it for a month and hope any toxin can be removed with regular water changes?
If I refill, what can I do to reduce the chances of it happening again?
 
What a nightmare! Has the water people been repairing any pipes nearby?
 
That's definitely a strange one, if you find out what the cause was do let us know.
 
Your dechlorinator was ? Prime ?

Not all dechlorinators will remove chloramine, which is added to water often in emergencies eg water main burst.

Also you test kits will also falsely read negative in presence of dechlorinators, so could have been ammonia poisoning from immature tank.
 
Firstly, sorry to hear you lost all your livestock, I know how that feels.

How long had you had the tank running with the new filter and how many fishes, shrimp etc did you add back to the tank?

Did you keep the Akadama from your previous installation submerged and aerated? I ask this because the bacteria that consume the ammonia and nitrite are aerobic and probably will not survive unless there is oxygen about.

From what you've said I'm thinking either ammonia poisoning or that when you've added the water to fill the tank you have dissolved some H2O2 or milton that has not been rinsed from the top of the tank. It's possible that you didn't have enough bacteria to deal with the addition of all your livestock in one go.

You could try an contact the water company and ask if there's been an incident that could have caused this -if nothing has happened then you could rule this out as a cause.

I hope you find out what went wrong.
 
I did speak to the water company and they have replaced a fire hydrant today, but that was several roads away. Even then the Fluval dechlorinator I have says it deals with chloramines.

The tank and pump had been circulating for the best part of a month. It had additional plants and water added about a fortnight ago. Possibly a short time, yes, but I don't think that's the problem for a couple of reasons:

A) Whilst the substrate was kept wet, but not aerated (so there is the potential for anaerobic respiration), in that time it managed to sustain several Amano Shrimp and Assasin snails I hadn't spotted when I drained it. They were alive for weeks in the small tank.

B) The fish all seemed health for the 48+hrs they were in the tank, were active before the new water was added, and were all dead very quickly and shortly after the water was added.

There were about a dozen fish, 8 shrimp, and I'm not sure how many snails. I did consider a NH4 spike, but all the fish were small (less than 2"), they were in 150+L of water, and again, the fact that all the deaths were in no more than 2hrs, and just after the water was added, does make me doubt that too. That the water tests showed negligible NH4, adds weight to that. I've not heard chloramines effect NH4 tests before, so that's possible, but surely the dechlorinator should have counteracted that.

If I've ****ed up with the cycling and/or stocking, I'll put my hands up, but the sequence of events strike me as significant.

Whatever the cause, any suggestions on how to proceed?
 
This is a very tricky one. Chlorine and Chlroamine wouldn't be that fast. Maybe it's a very acute toxin like cyanide etc that stops respiration quickly. Or maybe lack of O2 or high CO2 as mentioned. It has to be related to respiration and very quick acting as well.

Sorry about your loss.
 
I don't inject CO2 of use liquid carbon so I think that can be ruled out.
The tank is well oxygenated as there is a spray bar along the length of the tank and its jets were well above the surface constantly causing lots of air bubbles.

I know cyanide is used to catch wild fish, but I can't begin to think how that could be a factor in the circumstances.
 
Having experience something similar, I'd suspect the water ... in my case, roadworks were 1-2 km distant, did a water change as normal after driving past the construction, then watched fish die o_O :eek: :arghh:
The few that survived the night, died over ensuing weeks
I never measured anything unusual
 
I know cyanide is used to catch wild fish, but I can't begin to think how that could be a factor in the circumstances.
I meant similar to cyanide. Not cyanide per say. Cyanide blocks aerobic respiration and causes very fast death. Similar to what you saw. I'd be looking for a chemical with similar properties as the culprit as you have excluded all the easy stuff.
 
Sudden fish deaths like you are seeing, in my experience are nearly always due to chloramine being introduced into the water supply due to emergency water main issues. You are supposed to dose double (or more) dechlorinator if you use water with chloramine or suspect you have water with chloramine as chloramine is much "harder" to remove from the water.

My local fish shop had a week where a number of people who bought fish from them, came back a week later complaining all their recently purchased fish had died and also killed all their other fish. This was due to local chloramine dosing due to a major burst water main (was quite an impressive fountain). My water at home went slightly brown due to dirt for a day or two afterwards.

Also chloramine can be broken down, by some dechlorinators (not Prime), into the fish safe chlorine part (usually sodium chloride, common salt) and ammonia and it is the left over ammonia that kills the fish. At normal chloramine dosing the ammonia will quickly disappear in the tank, but when emergency dosing of chloramine occurs there is a massive ammonia spike. I notice Fluval dechlorinator doesn't remove ammonia.
 
Hi all,
There were about a dozen fish, 8 shrimp, and I'm not sure how many snails. I did consider a NH4 spike, but all the fish were small (less than 2"), they were in 150+L of water, and again, the fact that all the deaths were in no more than 2hrs, and just after the water was added, does make me doubt that too.
Bad luck, I think it was a water issue, rather than a "normal" ammonia spike.
I did speak to the water company and they have replaced a fire hydrant today, but that was several roads away. Even then the Fluval dechlorinator I have says it deals with chloramines.
That would be my suspicion. They may also have added more NaOH to the water which would have raised pH, and potentially converted NH4+ to NH3.

Because of the very quick deaths, a possibility is that they also treated the pipes to remove Asellus. <"When I lived in Bath we had Asellus in our tap water supply">.

I think <"they use CO2 to do this now">, rather than an insecticide, but they may still use a synthetic pyrethroid (like permethrin) with a low mammalian toxicity.

cheers Darrel
 
I shall call the water company again and see if I can ascertain exactly what they put in the ware.

It's not a crippling amount of money to replace the livestock, maybe £50-£100 but if they have added something that's caused the problem, is there is any chance of compensation, or is it likely to say "tough ***" in their small print?
 
Hi again,

If you've ruled out ammonia and nitritie poisoining this leaves 2 possibilities either toxic substances in the tap water or residual toxins form cleaning in the upper part of your tank.

You said you had the tank 60% full of water so potentially you could have had some residual peroxide or milton in the top part of your tank.
H2O2 - I believe fish are quite tolerant of hydrogen peroxide and from what I've read toxicity can occur in the 500 - 1000 ppm range. As you were presumably using a very dilute solution it is extremely unlikely that this is the cause. Also any remnants of peroxide in the tank would have dergraded quickly.

Milton - This contains 1% Sodium hypochlorite. Sodium hypochlorite is extremely toxic to aquatic life. The no effect concnetration is 0.21 ppm which means any concentration above this is likely to be toxic to aquaic life. However, as your tank has a large volume and the hypochlorite concnetration in Milton is only 1% I suspect that any residues would have been diluted to below 0.2 ppm.

So, excluding peroxide and hypochlorite toxicity the only thing we're left with is tap water toxicity. Unfortunately, there is nothng you can do about this. In your position I'd set the tank up again and add some hardy fish to see how they get on. If you know anybody who keeps fish in your area you could ask them to see if they've also had problems.

Just one more thing - You need to be careful using hydrogen peroxide and sodium hypochlorite as they can react together extremely violently. Have a look at the elephant's toothpaste reaction - this uses potassium iodide instead of hypochlorite but it's the same effect.

Anyway good luck setting up again.
 
Whilst the tank was only partly filled when I introduced fish, I think I'd been pretty thorough rinsing the whole tank before I even put the plants in, so I'd be surprised if that's the cause. I know it's easy to blame someone else rather than want to take responsibility for screwing up, but I can't think how I would have done so.

I wouldn't usually mix cleaners, which I haven't done in this case, but a useful reminder. I know the risks of chlorine based bathroom cleaners and descalers, and it wouldn't surprise me if an oxidising agent like H2O2 could liberate Cl in the same way. (Though my chemistry is nearly 30yrs old!)

Would you drain the tank and/or go through the cycling again?
 
Whilst the tank was only partly filled when I introduced fish, I think I'd been pretty thorough rinsing the whole tank before I even put the plants in, so I'd be surprised if that's the cause. I know it's easy to blame someone else rather than want to take responsibility for screwing up, but I can't think how I would have done so.
I think it's very umlikely that this is the cause but it's good to work through every possibility.

Would you drain the tank and/or go through the cycling again?
Personally, I would drain the tank and rinse with thoroughly with water and cycle again. I'd try woudl try to contact the water company again before adding any fish to try and undersand what happened. They may not be forthcoming but if you can find other people that have had the same problem that may help persuade them. Also. I'd use a conditioner that deals with chlorine and chloramine.
 
Nowadays they use plastic tubes and fittings for subterranian piping and the fittings have a kinda plastic(rubber) seal ring, to fit all together and make the tubes and seals slide easily into eachother they need to use lubricants. I've worked a while in the piping industry and very often dish washing soap is used as a lubricant. For us humans not realy toxic and it washes out relatively quickly.. But i guess for aquatic life it aint the most healthy substance to get in the tank.
 
This is hard to read and imagine.. so sorry for your lost my friend.

I don´t know by witch ways in your country you can oblige the water company assume your losses. But i wouldn´t rest and take a slip on it.. i would go to all institutions.

Here in Portugal, these kind of thing is taken very seriouly by our water company suppllier. (City Hall)

Once i was starting a WC and i smell a lot of bleach odor coming from the tap water. So i stoped imediatelly. I filled a great cup of water and record what was happening in the glass Lot´s of effervescence!. Then i present a claim to legal authorities with the video (ministerial agency of health and others) and to the city hall of course.
They answer and apologise that they were doing a special treatment according to something in that day.

So i claim back again to all Health Legal institutes and others that the city hall should previously warn citizens about this matters so that people be aware. And this is what is hapenning nowadays. Everytime the City Hall intends to make something in the tap water circuit they inform the population the day and the hour and time duration time of the interrunption.

I have no doubt that in that day if i did the WC i could kiss goodbye my live stock..

As concerning H2O2 simple forget it. In the past I dose massive and extremely H2O2 in my tank and never had a loss. Tested and tested over and over.

I don´t have any doubts the issue was on Tap Water. All occur after that.

Best regards

Sorry for so many writing errors .. i´m in a rush.
 
Is there anything that fish keepers can buy to test for Chloramine, like strips etc?
 
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