Dead fish, looking for answers

I got a call from the wife today around lunch. She calmly said one of the fish in one of the show tanks upstairs was dead. I told her to keep an eye on them and keep me posted. It sucks, but 1 fish dying randomly is usually not enough to alarm me. It happens. Then the next call came an hour later. This time she was panicking so I knew something had gone very wrong, 2 more dead, and the rest lost all their color. One was shaky at best. She moved them to one of my breeding tanks until I got home. The surviving group is seemingly recovering, but I have lost some of my favorite fish. All of which were the cream of the crop. Some of my best, hence the reason they were in my show tank. My red eureka jake, ruby red, and blue neon males all gone. I tested the water and it was fine: 0/0/20. Ph, hardness, and temp all perfect. Last water change was about a week or more ago.I generally do 50% about every week and a half. They were perfectly fine last night and fine this morning during feeding. No external signs of disease or parasites. The only thing that has changed in the tank was 2 korelia 600's I added yesterday to give the tank some more circulation. They were brand new from the box so I can't see them being a problem. I'm lost here, and have no idea why it crashed. I plan on doing a water change when I get back tonight but I am a little hesitant to put them back in there. Any ideas? Anyone else have random death like this?

Sorry to hear.
I once had a strawberry peacock who die with no prior signals of sickness.
Water was fine and there have been no changes to the wc routine.
He just died. The rest of the fish were fine and no other has died.
I never figured out what happened.

I wonder if they could get sick/weak and the others bully him?

I have had random deaths but if its more than one its never random. Most toxins in water are undetected with a test kit. If the ONLY variable is the koralia I would examine them and the boxs they came in. Was there any cleaning done in the room with the tank? Doesn't have to be to the tank just anywhere near the tank. Any aerosols/chemicals? Any aquarium products/chems (conditioners, meds, anything you add to a tank)? Any fish added without qt first?

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I thought that when she called about the eureka. But then 2 more and the rest colored down. I can't figure it out

Is it possible that the Ph was low and that ammonia was present prior to adding the koralias? If this is possible, the additional surface agitation could add enough oxygen to impact the Ph and make the ammonia toxic.

I admit, this is a long shot, but it is possible.

At this point I would say anything is possible as well. The only variable was the korelias. I put them in last night but what could be up with them? It does seem too coincidental. I will take them out and wash them real good in case. I added 1 new fish last Monday from Aquamania. He was quarantined for 24hrs in my hospital tank. No house cleaning was done. The wife has been trained for sometime now plus her standard cleaning day is wed. I did ask just in case and she gave me the do you think I'm stupid look. Agreed not all toxins can be found with the test kit. Ammonia, nitrites, nitrates, hardness, and ph all good. Nothing was added to the tank. The only chems I use is prime during water changes and that was a week or so ago. All I know is when 3 fish die out of nowhere something is wrong and I am scared to death to put them back in there.

got similar problem at one time with the new filter DID NOT RINSE IT.removed the filter and used my old filters back to normal again used the sponges juices on my new filter and had the same problem.did the old filter again ,prewashed the new filter (rinse) really good got it hook up and no more problems (couple fish die) in the mean time gasping for air etc..I'M CONVINCE THAT PRE-WASH THAT I DID NOT DO KILLED MY FISH.PD i learn as i kill.

I think Dan was on the right track. Sounds like some sort of outside toxin was added to the tank. Could be and air freshener or something like that. Hope you figure it out.

Sorry for the losses. It sucks when we inexplicably lose fish.

u should be glad your wife called and took action!!!

If you added the Korelias and fish died the next day -- I'd blame the korelias. Whether or not it's a toxin or an electrical short or whatever, I'd pull them and I'd do a big water change with aged water.

so sorry. losses just suck.

Maybe toss some some less important fish in first. Hate to use the word worthless fish so maybe something with less emotional significance or less financial burden. Atleast that sounds a little better.

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Was the new fish from a club member or a retail vendor? If it was a vendor I could probably guess who and also possibly determine the cause. Only thing strange is that the fish got better in a different tank. This wouldn't happen with the parasitic explanation I would lean towards from a vendor.

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Yeah that's a good idea. Ill try that for 24 hours and see what happens. The tank right next to it has 40+ fish and no problems so I doubt it was a cleaner or aerosol. Ill empty the tank, clean the korelias, add a couple fish, and see what happens.

I've had something like this happen.
I did a 50% waterchange on one of my tanks and half an hour later I check on it and half the fish are dead and all of them have this weird white fungus stuff all over them. All of the fish's eyes and gills where completely covered. Sometimes when I'd scoop out some dead fish they'd start twitching allot and suddenly just die. My stingray, peacock bass, arowana, all of the fry from my texas/jack dempsey hybrid pair, my paratilapia bleekeri, lots of plecos -mainly bn plecs but a gold nugget and green phantom where also in the tank at the time-, ect. where all dead within an hour. It was one of the saddest things that has happened to me in the hobby. Unfortunately this was my main display tank with all of my favorite fish in it. And to this day I still dont know what did it.

This is reading like a X-File.

I think Andrew may be on to something with the increased water agitation.

Your tests came out fine.
The fish are recovering well in another tank (but in the same room) - that seems to rule out aerosols/cleaners (assuming both tanks are covered).
The fish that you added last Monday, what is its status? Is it alive? If it alive and is the cause of the deaths of the other fish, I guess you may start seeing some of the fish in the new tank also get sick.
Given the rapid decline, I think the problem is with the Korelia's (either them being dirty, electrical problem, or something to do with the increased water agitation). I think I would remove them and go from there.

Ok to clear some things up. The fish was from a vendor there. I don't want to mention the name as I have no idea if it is the problem. He is still alive but is the only one Still a little shaky. He is not the cause of Aggression or stress deaths as he is much smaller then the rest and seems to be scared of them. The fish are not in the tank next to it, I was just mentioning that there is a tank next to it with 40 plus fish in it and they are fine. The fish are now recovering in a breeder tank downstairs by themselves so they don't get anyone else sick if it us a parasite or something. I am getting ready to empty totally, remove and change the rocks, refill and add my rift mix and some prime, and let sit for a day. I will remove the korelias but without them there is very little surface agitation as I am running an fx5 not an hob. That's why I bought them. Having said that the fish have been in that rank for a long time with little water movement with no problems. I just bought the **** things. I wish I had an easy way to ck for electrical current in the water. I'd love to check dissolved oxygen before I broke it down too but I have no way to do it.

I would say the korelia 600.

With stuff coming from overseas countries it is quite possible that it was a time bomb in a box. I know there have been lead paint on the toys in Happy Meals, milk suppliers being executed ( as in firing squad ) due to industrial chemicals being added to powdered milk so they could water down milk regardless that it killed 6 and hospitalized 100s of thousands infants, and adding chemicals that convert to the date rape drug in children's toys, it is hard to say what is in the box.

It is a shame you do not have another to get it analyzed.

I have 3 850s in another tank. I had 2 brand new 600's in this one that I just put in last night. Maybe it's not a coincidence. Who the heck would analyze them? Doug can't you write some kind of computer program to do that? Lol by the way everyone seems hunky dory at the moment in the breeder

I would think...... you could take it to a water testing place and have them do it, but you would be out money, but then you might have a claim against the retailer. Hardware is cheap, good looking fish are not.

BTW, I am allegedly in IT, just on the down low as I only work 1 or 2 days a week.

Just an update. Been 12 hrs back in the tank and so far so good. Left the korelias out.