# Catastrophic Fish Die-Off



## jtma508 (Jan 1, 2008)

I've just had a massive fish die-off in my 72gal freshwater tank. It was the most precipitous die-off I have ever experienced. Water quality tested fine across the board (74deg, ph 6.7, NH3 0, nitrates/nitrites 0, ORP ~400). The first morning I lost 2 large angel fish, a paradise fish, a belonglanis, 2 clown loaches (that were over 8yrs old). Over the next 48hrs I lost a younger clown loach, a lge Australian rainbow, black khuli loach, lge algae eater (>6yrs old), red tail shark, synodontis and I decided to euthanize an 8yo, 12in pleco.

On the morning of the initial die-off I immediately began treatment with LifeGuard.

None of the fish had any outward signs of disease. Those that we saw die (that didn't die overnight) went from lethargy to death in a matter of an hour or so.

The only fish with any outward signs was the large pleco. We noticed this morning that he had clear pustules measuring between .125 and .25in on both lower edges of his tail fin, in areas of his pectoral fins and some on the base of his dorsal fin. We hadn't noticed this prior to this morning (although he was hard to observe since he liked to hide behind a stone wall in the tank). A small number of these pustules had blood and there was some blood streaking in fins. The pustules were thin-walled and undulated in the water. 

We took some pictures (not fabulous quality unfortunately) of the pleco that I'm posting. Obviously I need to determine what the underlying casue of this plague is and am hoping you folks can help me so I can save the remainder of the community.

Thanks and Happy New Year.


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## herefishy (Dec 14, 2006)

I have, in the past, experienced similar die-offs. I have run the gamut of fixes, from loading with meds to heavy water changes to removing the infected fish to hospital tanks (sometimes that just allowed them to die alone). I have found that performing massive water changes, as much as 75%, and adding PimaFix and MelaFix, in combination, according to label instruction (be sure to remove all carbon filtration), has proven to be the most effective remedy. You may not be able to save all of them, but you should be able to rescue a majority. A dose of StressCoat will also help the fish to re-establish their slime coat.


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## Lindsey88 (Nov 23, 2007)

It sounds as though the water could have been contaminated has there been any sprays or anything spilled in there by accident? Sorry for your losses.


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## jtma508 (Jan 1, 2008)

No. Nothing chemical near the tank or any of the tank's components. I think the attached pictures of the pleco are telling. It seems like a pathogen of some sort. LifeGuard doesn't appear to be stopping it. Fish are continuing to die (3 this morning). Now it's the younger, smaller fish that are dying off.


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## jumpereb (Jan 1, 2008)

*re*

i think its fin rot but im no expert


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## johnmaloney (Nov 21, 2007)

Sorry to hear about it. Nothing worse than watching your fish die. I hope you have some luck fixing the problem.


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## jtma508 (Jan 1, 2008)

I'm quite sure it isn't fin rot. And at this stage it's all but over. Just about everyone has died. I think I'm down to a black khuli loach, a couple corys, a couple siamese algae eaters, a couple turqoise rainbows and a pradise fish. All small. I've never seen anything like this.


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## Amphitrite (Sep 8, 2006)

Sorry to hear you've lost so many fish - you must be gutted. It's even worse when you can't find out the reason behind it. 

I'm just wondering, do you use water from the tap when doing water changes? If that's the case, then maybe the water company has treated the water with something which isn't showing up in the tests.


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## herefishy (Dec 14, 2006)

There can be many reasons for catastophic fish die off. Many causes are the things we take for granted and do everyday. This includes cleaning and cooking. Yes, I said cooking. So, be careful what you do areound your tanks. If anything you may do, you have a question about, play it safe. Turn off any air pumps and cover the tank.


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## jtma508 (Jan 1, 2008)

The tank has been 'up' for almost ten years. I've had crises before (infrequent) but they've always been manageable. I have always used water from the tap for changes but we have deep well water so its chemical makeup is quite constant. I don't know what got in there or how but whatever it is it is incredibly pathogenic. There's no saving anyone. I'm going to have to sterilize the system.

May be time to go marine.


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