# Tank crashed overnight - any feedback welcome



## CHK (Jan 12, 2007)

Hi guys,

This is a tank I have helped a friend set up in his waiting room. This morning, when he came in, this is what he found:
1) Water very milky
2) 9 dead "electric blue" johannis
3) 7 dead yellow labs
4) 1 yellow lab gasping at the surface, 2 albino BN still alive
5) Food deposits stuck on the filter intake

He did a 50% water change and I came in a few hours later to see whats going on. The fish were perfectly fine as of 4.30pm yesterday when he fed them. Water was clear and all fish ate. I came by at 2pm and tested the (still cloudy) water - this is what I got:
ammonia: 0ppm
Nitrite: 5ppm (top of scale)
Nitrate: 80ppm

This is a 55 gallon that has been set up and running steady (cycled) for a 6 weeks already. It took a prior month to fully cycle.

Water change regimen is 50% weekly and fed only NLS twice daily. So we went from perfectly fine tank to a dead tank in about 16 hrs. Does anyone have any idea what might have happened? There is a potential clue though, right after my friend left his office at 5pm, the cleaning people would come in every tues night to clean the office and the lid of the tank was left open. I want to rule out all possibilites before "accusing" the cleaning pple, since I do not have proof. 

Thanks!
Chong


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## Adrnalnrsh (Mar 18, 2008)

Cleaning people use products on around the tank?

Nitrites aren't suppose to be up at all on a fully cycled tank and nitrates are really high.

What water conditioner was used?


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## CHK (Jan 12, 2007)

Prime was used.

I suspect that the high nitrites and nitrates was because of the fact that the fish suffured or died very soon after eating so the food was regurgutated out and fouled the water...

Thanks for the reply!


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## Robin (Sep 18, 2002)

A few things stick out to me in your post.



> Food deposits stuck on the intake.


 If the intake became clogged or if the filter media was clogged with uneaten food then this may have cut off air to the filter which may have caused the nitrifying bacteria to die. This scenario will kill fish fast. Open the filter and have a look at the media. Check and see that there is a good strong flow of water coming from the filter return. 
Also, re-test for ammonia. 



> the cleaning people would come in every tues night to clean the office and the lid of the tank was left open.


 If they sprayed _anything_ in the area then this could definitely be what killed the fish. Also if anyone put their fingers in the tank the slightest soap, gasoline, cologne residue can be fatal to your fish. (Never pick up the fish's food with your fingers!)



> This is a 55 gallon that has been set up and running steady (cycled) for a 6 weeks already. It took a prior month to fully cycle.


*Questions:* What method was used to cycle the tank? Where all the fish added at once?

For now I would advise your friend to do daily or every other day partial water changes of 40% using the Prime at the full recommended dose. To help detoxify the nitrite, (nitrite should always be 0), add 1-2 teaspoons of salt per ten gallons. Feed the remaining fish sparingly--one small feeding a day.

Anytime you have a massive and symptom-less die-off the first thing you should suspect is a problem with the water. Especially if the remaining fish are gasping at the surface. He no doubt saved the remaining fish with the water change but if the filter is clogged or broken then you can expect to see them stressing at the surface again.

Please post back with more information.

Robin


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## CHK (Jan 12, 2007)

Thanks Robin for the analysis. Let me try to address your queries:

It is possible that food clogged on the intake may cause pump failure. However, when he fed them last evening, all food was eaten. It is a Rena Xp2 and the filter never stopped running. All the fish are still small, at 2 inches or under and should not die overnight even if the filter got clogged?

I did not believe that ammonia was zero too. I retested on the spot (API Master test kit), and even shook the bottle, but it is correct. Do you think when the water was changed 50% prior to water testing, the Prime added may have removed the ammonia?

Perhaps cleaning chemicals did cause the tragedy  . We will have to work on that with the cleaning people....

During cycling, the fish was added in batches and water quality was monitored throughout, so I am fairly confident it was not a cycling problem.

I have taken custody (so to speak) of the 3 remaining fish in my Q tank. I think we shall rinse everything out and start from scratch.......

One thing that disturbed me was that the water was really cloudy or milky. What is that a symptom of?? :?

Thanks,
Chong


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## Robin (Sep 18, 2002)

> All the fish are still small, at 2 inches or under and should not die overnight even if the filter got clogged?


 The size of the fish wouldn't prevent them from being affected. When the filter becomes clogged the beneficial bacteria die and ammonia spikes. Checking the filter is something I often suggest when there's a sudden unexplained die off and where you mentioned food on the intake I thought it was even more likely that something may have been clogged. 


> Do you think when the water was changed 50% prior to water testing, the Prime added may have removed the ammonia?


Yes.



> I have taken custody (so to speak) of the 3 remaining fish in my Q tank. I think we shall rinse everything out and start from scratch.......


I wouldn't start from scratch. It really doesn't sound like anything in the way of disease. Sounds like either a toxin got into the water or the filter got clogged. If you start from scratch then you'll loose any beneficial bacteria you've got in your filter. Instead I would do a few partial water changes with the Prime. If the fish are out of the tank for more than a few days then the tank will no longer be cycled.

I'm wondering if this tank was in fact cycled to begin with. You didn't mention the method you used.

Robin


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## CHK (Jan 12, 2007)

Thanks Robin,

For the cyclng, when the tank was set up, 8 tetras were used as cycling fish. I also seeded filter material from my mature tanks among the new filter's material. When the nitrites were clear, we added fish and removed tetras over a period of 2-3 weeks, all the while monitoring the water quality.

The filter, however, wasnt clogged as there was still strong output. But based on your advice I will open the canister tomorrow and see what I find....

I think you have a point - perhaps better to dilute and remove toxins via WC than to start from scratch. Lets see if the water is still cloudy tmmrw. We shall return the tetras to the tank and see how they do.


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## 6stang9 (Oct 26, 2007)

It sounds to me like they may have drowned. Was there enough breakage at the top of the water to allow for gas exchange? This is very common when you hear of so many fish dying in such a short time. Do you have any breakage such as an air stone, power head or filter return, up high enough to cause turbulence on top of the water? The dead fish would cause the cloudiness in the water by the time he got back to work. I dont think that all the fish would have eaten at 430 and be dead by the next morning because of biological failure. I think you would have noticed something befor that happened. If the didnt drowned then it could very well be that some thing got in the water from the cleaning agents that were used. Cover that tank! Good luck


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## Robin (Sep 18, 2002)

> For the cyclng, when the tank was set up, 8 tetras were used as cycling fish. I also seeded filter material from my mature tanks among the new filter's material. When the nitrites were clear, we added fish and removed tetras over a period of 2-3 weeks, all the while monitoring the water quality


Sounds like you did everything right with the cycling. The water may still be cloudy tomorrow, and even a month from now if its a bacteria bloom. Smaller, more frequent partial water changes may be better than large ones when trying to get over a bacteria bloom.



> I dont think that all the fish would have eaten at 430 and be dead by the next morning because of biological failure.


When you have a sudden die off of all your filter bacteria it actually will kill the fish that fast. But we don't know if that's what happened here. Keeping the tank closed with a request to the cleaning people to avoid spraying anything near the tank is a good idea. 

Robin


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## CHK (Jan 12, 2007)

Robin,

Thanks for the all the help rendered. I think its really scary that you can lose your whole tank overnight. More than the cost of fish, its all the effort setting up the tank and attachment to them thats gone down. The cleaning pple have been given strict instructions to leave the tank alone from now, assuming its them.

One point though, not to disagree with you completely, but I could see 6stang9's point. If the bacteria in the filter all died of a sudden (perhaps they used anti bacterial spray for eg or the filter intake clogged), wouldnt it be akin to a power outage? In the case of power outage once, I was able to maintain all my fish for a day and a half in essentially the same tank without losses - and the tank was more heavily stocked than this one.


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## Robin (Sep 18, 2002)

> In the case of power outage once, I was able to maintain all my fish for a day and a half in essentially the same tank without losses - and the tank was more heavily stocked than this one.


To be honest with you this is something that I've never been clear on: just exactly how long do we have when the filter is turned off before the fish start to suffer? Like you I've had power outages that lasted for hours at a time and all fish survivedâ€"(I did do water changes during the outage). But I've also read of experiences here on the forum where entire tanks were lost under the same circumstances.

I think the answer may lie, in part at least, to the variables between tanks. For instance if the filter bacteria suddenly dies off due to complete lack of O2 then there will be a spike in ammonia. How much of a spike would depend on how much bacteria died--so that's one variable. Then you'd also have to consider the ph level of the tank. At lower ph levels ammonia is not toxic to fish. So if you had a tank with a ph around 7 the ammonia spike would have little or no effect. If the PH was up around 8 then you could expect the fish to be seriously effected. 
Other variables would be water tempâ€"higher temps hold less O2 so that would effect both the fish and the filter, fish load, the type of filters used, (a HOB would have more exposure to air than a canister), etc. 
I donâ€™t know for certain what killed your fish. You mentioned food on the filter intake and that caused me to wonder if the filter suddenly became clogged. It would also indicate an excess of wasteâ€"perhaps a history of overfeeding the fish, and all of this could have played a part in the sudden death. 
Generally when someone reports numerous, sudden, (overnight) fish deaths thereâ€™s a few things we can look at: toxin in the water, a problem with the filter, aggression, (although youâ€™d normally see one or two deaths at a time with aggression), or a fast moving bacterial infection such as Columnaris. 
Surprisingly itâ€™s not that uncommon for someone to loose their entire tank overnight. Iâ€™ve dealt with it quite a few times here on the forum. Sometimes through discussions like this we can figure out what happened but not always. In the case of toxinsâ€"soap, gasoline, cleaning productsâ€"thereâ€™s no test we can do on the water to know for sure. Evidence of an ammonia spike can be lost when the aquarist does a large water change in response to seeing his fish gasping at the surface.

Okay, I'm late to work!
Robin


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