Minnow Die off

Bullsnake

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Have been keeping our own minnows for a few years now in a 72-gallon tank and have not been able to keep them alive this year, have treated our tap water like we used too, used well water, river water and they keep dying off in large numbers fairly quick. only thing I can think of is that it is the tank, Aluminum, but can't find nothing to say that that is the case. Any help?
 


guywhofishes

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Have been keeping our own minnows for a few years now in a 72-gallon tank and have not been able to keep them alive this year, have treated our tap water like we used too, used well water, river water and they keep dying off in large numbers fairly quick. only thing I can think of is that it is the tank, Aluminum, but can't find nothing to say that that is the case. Any help?
What's their behavior prior to dying? Erratically dashing about?

What's the aeration/filtration system?
 

701FishSlayer

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If you've never had a problem before it just might be dumb luck. Once one dies its a snowball effect pretty quick if you don't get the dead ones out quick enough.
 

Davey Crockett

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I agree with retired guy, sometimes they get the itch and rub against the side of the tank when that happens.
 


Fester

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I suspect the aluminum tank no longer has its coating and is poisoning the minnows. I had it happen in a deep freeze set up for chubs. Now I use a cattle watering poly tank and no issues.
Curious how an aluminum tank could kill the minnows? Is aluminum poisonous to fish?
 

svnmag

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I'd be looking at all the above along with temperature. Maybe you could add some "miracle CBD" to the water. :p
 
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Lycanthrope

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Once minnows start dying it can be hard to stop. Id suggest tossing all the minnows, clean your tank and refill it and add a cup or two of bleach, let it set for a day then rinse it again and start over with fresh minnows.
 


scrotcaster

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I suspect the aluminum tank no longer has its coating and is poisoning the minnows. I had it happen in a deep freeze set up for chubs. Now I use a cattle watering poly tank and no issues.
Can i be bold enough to ask about your poly tank setup ? will it stay cold enough in a garage ? what kind of filtration setup ?
 

guywhofishes

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I was hoping OP would answer the questions. Hard to help without feedback.

I suspect stray voltage from a pump or lack of a functional nitrifying bacteria biomass that was previously doing its job.

Stray voltage causes the minnows to dash around erratically for an hour or two and tip over - one by one. Easily remedied with a $10 Amazon purchase.

A functioning biomass is easily accomplished too - but why did it quit working?

Could be a disease - but without feedback (symptoms displayed by the fish) it's awful tough to diagnose/treat.
 

Chas'n Tail

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Don't overlook getting some basic pH balancing solution you can get at any pet store and throwing a cap full in. If you don't have a testing kit, might be a good idea to get some water treatment solution too. Filtration is good, but more importantly is checking your levels and water temperature. Consider freezing gallons of water and rotating the jugs out on the daily to keep your water cool. Ideally it should be below 45 degrees.
 

Captain Ahab

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If you get a "bug" in your filtration system it will continually happen. Heavily cleaning filtration or scrapping for new filtration has rid me of this problem in the past.
 

Davey Crockett

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Have been keeping our own minnows for a few years now in a 72-gallon tank and have not been able to keep them alive this year, have treated our tap water like we used too, used well water, river water and they keep dying off in large numbers fairly quick. only thing I can think of is that it is the tank, Aluminum, but can't find nothing to say that that is the case. Any help?
Are the fish biting ?
 


guywhofishes

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The pump/filter system can develop a short circuit to the tank water. The swap out of the entire filtration system cures the problem - but it wasn't the filtering process biota or a disease causing the problem. It was stray voltage - that got cured by the swapping of new components.

A $10 titanium aquarium ground probe from Amazon is cheap insurance.
 


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