Killed my Leporinus after water change??

[TonyRs5]

Today my 3 Leporinus in my 125 community tank died within hours of a 30% water change and I have no idea why, definitely bummed out.  Prior to the water change which I do about every 12 to 14 days the water parameters were normal, maybe about .05 ammonia and all else normal.  I have no idea what happened as they have been through several water changes like this one before and every other fish, loach, and snail in the tank are fine.  The water temperature never varied more than about 1.5 degrees, I use a laser thermometer for the tap water.  After each water change I add prime and Pristine as directed and a little carbon(flourish) for the plants.  I tested the water after a few hours, ammonia at 0, nitrates around 30, all others the same as always, any ideas?  I really liked these 3 fish and now I am afraid to get more.  

Edited April 18, 2022 by TonyRs5

[Beau Burkhalter]

Do you have any airstones or oxygen source besides plants?

[TonyRs5]

Yes, two airstones and several plants, just added a new large plant a few days ago.

[Wrencher_Scott]

On 4/17/2022 at 5:33 PM, TonyRs5 said:

Today my 3 Leporinus in my 125 community tank died within hours of a 30% water change and I have no idea why, definitely bummed out.  Prior to the water change which I do about every 12 to 14 days the water parameters were normal, maybe about .05 ammonia and all else normal.  I have no idea what happened as they have been through several water changes like this one before and every other fish, loach, and snail in the tank are fine.  The water temperature never varied more than about 1.5 degrees, I use a laser thermometer for the tap water.  After each water change I add prime and Pristine as directed and a little carbon(flourish) for the plants.  I tested the water after a few hours, ammonia at 0, nitrates around 30, all others the same as always, any ideas?  I really liked these 3 fish and now I am afraid to get more.  

Best guess, chlorine

Do you get regular tap water like from the city? I know you used Prime but sometimes they super chlorinate and if you aren't careful the Prime isn't enough. I've seen my tap go to over 2ppm at times, it's normally under 1. I've heard they will sometime throw 4 ppm at it. 

I always test for chlorine after I dechlore just in case. I've heard a few horror stories. I use about 3 times the dose on the bottle, Prime says 5 times is safe IIRC. 

I can usually tell from the smell if they overdue the chlorine. 

[Beardedbillygoat1975]

I’d worry your water company did a flush of the pipes with a chemical of some sort and it’s was just a matter of bad timing. You can call them and see.

Have you checked the parameters of your tap water to see if anything has changed? Sometimes there’s chlorine and chloramine but Prime should have sorted that for you. How old is the Prime? Is it expired?

Did you do a big gravel vacuum after not doing one in a long time? I’ve had a couple of occasions where this has released some pockets of gas that certain more sensitive species couldn’t handle. The hardy ones can hang for a few hours with an ammonia or nitrate spike but some fish just can’t. 

[TonyRs5]

I did a gravel vacuum, however, it was actually pretty clean as they are done bi weekly.  I think that based on what I am getting in replies it was most likely something in the tap water and unfortunately I missed and the Leporinus could not handle it for some reason.  I will get a tester for chlorine and going forward I will need to up my dose of prime as precaution(new bottle was used), it is city water and god knows what they do to it.  As much as I hate losing them I am lucky there wasn't more fallout.  Thanks. 

[GardenStateGoldfish]

If you live in the united states and get municipal water, this time of year they do flushing and they add a lot of chemicals in (usually just super doses of chlorine or chloramine) which sometimes require more than the labeled amount of prime. 

Sorry for the loss of your fish, I have chloramines which are a nasty thing, I never do water changes after large storms or during flushing anymore just to be safe, but triple dosing prime works great for the chloramines. However, you said your ammonia test was 0 which rules out chloramines, it would have had to of likely been chrorine if it was something in the water which is less likely since you did add prime. 

Stray current maybe? forgot to unplug the heater before the water change and broke it? 

[TonyRs5]

Thanks, at this point I have considered electricity as well, however, I turn off my power strip prior and the weird thing about the whole situation is that it only affected my 3 Leporinus, even the chemical possibility doesn't explain it. I suppose though that the city did add something and we are not aware of it, that can't be ruled out.  At this point I can only go with some type of stress that this particular fish could not handle, hopefully it does not happen again, they are cool fish.

[Dawn T]

On 4/17/2022 at 7:01 PM, Wrencher_Scott said:

I can usually tell from the smell if they overdue the chlorine. 

Had that issue in our previous town. They OVERchlorinated the water so badly a couple of times a year, I couldn't hardly stand to take hot showers because of the fumes. I OVER treated with dechlorinator during those times, or left the water sit for at least 24 hours if I could before using it.

Thankfully haven't had that issue where we live now, but I still pay attention for it.

@TonyRs5It truly is bizarre that only the Leporinus were affected by whatever. I don't remember reading anything about special sensitivities for that species over others, but it's been a while since I looked into them (a friend bought some a long while back). I hope you find answers though!

[TonyRs5]

Thanks, yes, I am now using more Prime just in case and the Leporinus are not particularly hard to keep, they are quite hardy fish and very cool to watch, very strange for sure.  I have already replaced one and will buy a few more, hopefully it does not happen again.