All Fish Dead!

[fishlove75]

Hello,

Not particularily an emergency now since almost all the fish are dead but would still like to try to figure out what went wrong. So here is the story.

I have had a 12 gallon Marineland Eclipse tank up and running for a little under 3 years. The tank was fishless cycled, no major issues with cycling. No live plants, sand substrate. The tank was going fine with 8 Harlequin rasboras, and 2 nerite snails. Absolutely no issues in the tank. No evidance of disease, parasites etc. All fish acting completely normal. All water stats fine (ammonia 0, nitrite 0, nitrate was 15 before the water change and deaths ph at 7.2 which has been stable at 7.2 for the entire 3 years). So I did the weekly water change, cleaned the dirt off the sand and stirred the sand, all standard routien for my water changes. I use Prime dechlorinator. I woke up the next morning and found 2 fish and one snail dead. I checked stats ammonia 0, nitrite 0 nitrate 5 ph 7.2 temp 76.2 F. Went to work and when i got home there were 4 more fish dead. I now have 2 fish left and one snail, and they seem to be acting normally, as did the other fish prior to thier deaths. There has been absolutely NO CHANGES in the tank for 3 years, I was away for 15 days got back 3 weeks ago. Did a water change before I left and immediately when I returned. There has been a total of 3 water changes sice I got back. However this water change caused all the problems. I have 3 other tanks, also had water changes and cleanings on the same day. I get my water prepared in a big plastic tub and add the prime. The water in the tub is then used in all my tanks but I only had problems in this tank, the other 3 tanks are completely fine. The water in the questionable tank was 76.2 degrees F (also standard for this tank) the temp of the water for the water change was 76.0 F. Nothing got into the tank, nothing got into the water used for the change (and if it was an issue with the new water why am I not having problems in the other 3 tanks?) I have no idea what happened. Any ideas?

Also, water stats following first deaths ammonia was 0.0 nitrite 0 nitrate 5, ph was 7.2. Stats following the second deaths was ammonia 0.25 (my guess from the 4 additional deaths I work 12 hour shifts so It is possible that the 4 that died in the second round of deaths were dead in the tank for 8+ hours)nitrite 0 and nitrate 5 ph 7.2 and no change in temp. Did a water change after each set of deaths So other then the slight ammonia (using api kit) there was nothing major in the water stats the next morning.

Now I was planning on moving my rasboras into my larger 55 gallon tank, and actually shutting down and possibly selling my eclipse tank (long story). So now I am not sure if I should move the remaining 2 fish or not. Any ideas would be helpful, just not sure if I should move the remaining fish/snail and try to sell this tank as planned or just throw it out.

Thanks

edit: Wanted to add that the dead fish looked completely normal, no red gills, no sign of injury, disease or parasits. Just found them floating up side down in the tank.

 

[Piti]

Maybe some soap from the cleaning materials got in the tank? Easy mistake to happen... Clean bucket with soap, then mistakingly use for tank water (even a week later sort of thing) Or some other form of poison?

 

[fishlove75]

I thought of that, but I have completely different buckets that I use for tank cleaning. I only use them for that purpose they are not used for anything else other than my water changes. I have a 55 gallon, a 29 gallon, the 12 gallon and a 5 gallon tank, and I changed the water in the 5 gallon first then the 29 gallon, so if it was an issue of something in the buckets or the new water (ie soap or something) then the 5 and 29 gallon tanks would have received the bulk of a toxin if it were present, and those tanks are perfectly fine. I changed the 12 gallon after the 29 gallon and the 55 gallon last, using the same buckets for each tank and the other tanks are perfectly fine, only the 12 gallon tank was affected. The buckets and equipment I use for water changes are kepted in the storage part of the 55 gallon tank stand so they would not have be used for some other purpose by accident. And even if they had, the 5 and 29 gallon tanks would have received the posion first and as I said before those tanks are fine.

It really is a mystery I just can't figure out why one tank was affected and not all of them. The water came from the same source, I filled up my large 50 gallon rubbermaid tub like I always do and used the water from that tub to change all the tanks (dechlorinated with prime). I just can't figure out what happened. I thought maybe my dechlorinator was bad. But again, if it was the dechlorinator, then by logic all the tanks should have been affected. I just don't know.

 

[Jackiee]

I have no advice to give on this, it's absolutely puzzling..
Very strange..
But, i'm sorry about your loses!



I'm sure you would've noticed if their were any weird smells from the tank water,

 

[fishlove75]

I know it is very odd, the second snail died the next day, but the 2 remaining Harlequins are still doing fine. I moved them into my big tank and completely stripped that tank down. I was planning on tearing down that tank anyway so no big deal in the loss of the physical tank, but loosing 6 fish and 2 snails in a matter of 48 hours really sucks. Well I guess it will remain a mystery. I still don't quite understand what happened. There was absolutely NO sign that anything was wrong, no smells nothing. It is really weird. I have the tank sitting empty, my plan was to try to sell it, but now I am nervous to do that, if there is something funky in the tank I would hate to pass it along to someone else.

 

[Parasaurolophus]

Sorry for your loss, Harlequin rasbora can live for 3-5 years, do you know how old they were when you bought them?
it could have just been there time since everything else seems fine....

 

[Rynofasho]

How often have you stirred the sand previously? Maybe you had an anaerobic pocket in the sand that you disturbed?

 

[Jackiee]

How often have you stirred the sand previously? Maybe you had an anaerobic pocket in the sand that you disturbed?

That's what I was wondering too.
That's why I mentioned I'm sure she would've noticed if there was a funky smell to the water.
I've had two tanks completely wiped out from anaerobic bacteria outbreaks with hydrogen sulfide poisoning in the past.

HORRIBLE rotten egg smell. filled my entire apartment, and could be smelled from the hallway coridor before you even entered my apartment.

The first time, I lost my male parrot fish (I had a pair, a male and a female that bred) the female survived,
along with only one yellow guarami. I had about 7 fish when this happened.

I restocked my tank gradually again, had about 6 fish,
then it happened again. lost every single one except for my female blood parrot once again.
This time, in a period of 30 minutes, my tank went from seemingly fine, to all my fish laying at the bottom, not moving, barely breathing.


It's a terrible thing to lose so many fish in the blink of an eye. I feel her pain.

 

[LilyRose Tank]

I know this is a long shot, but you say you have had these fish for 3 years. Is there any chance they could be reaching their natural mortality. I understand that the snails have perished too, but snails have a varying lifespan depending on diet and temperature too. Is this a possibility?
sand stirring has killed a few of my fish in the past as the toxic fumes in the sand are released. if you do this regularly it is supposed to cut down on the gas build up x

 

[fishlove75]

Hi, no I don't believe it was anerobic sand, I stir religiously every week, and there was no smell to the water.

I thought about the "natural causes" which I suppose is possible, but it would be weird for 6 fish and 2 snails to all die with in 24 hours of each other if it were just "old age" but not impossible I suppose. The nerite snails have a life span of 1-2 years and I had those for a little under 3 years. Same with the harlequins (had for 3ish years) but I have no idea how old they were when I got them.