Sudden fish loss

[Astroman]

New to this site-first post!

My 30 gallon tank developed a leak after 30 plus year three days ago. Tank was cleaned 3 days ago , no losses in tank over 6 months . The tank housed 3 Cory's, 7 tiger barbs, one cherry barb and a rhomboid barb. The last two were long term survivors from other tanks.

New tank to transfer to is 72 gallon with rosy barbs and giant danios. This tank is up and going for 2 plus years. Both tanks w 0 ppm on ammonia, 0 nitrite and 5 ppm nitrate. I have been pre- mixing in 25% RO water to the 30 gallon tank, but not 72 for last 6 months.

I added water from home tank into two bags(used same type before) and floated in new tank. I have used drip and bag method both in past. Fish were distributed equally. I added 6 oz water from new tank into each. In 5 minutes all fish except Cory's swimming erratically . I added prime to bags then immediately moved distressed fish back to home tank. Cory's stayed in bags and later released in new tank without issues. Other than rhomboid barb, all others died immediately. Tested water in bags-0 ammonia and 0 nitrite, ph same as home tank. What happened?

 

[Thyra]

Looks like no one else has any ideas either. I remember a long, long time ago we brought some small - like 2" fish back from a tidal pool in a bucket of the same water. We put them in a homemade tank - which was probably less that 5g and they suddenly all started swimming very erratically and fast and were dead very quick. That was over 50 years ago and I still think about it and wonder was it temperature, oxygen or just the confinement? We were very naive at the time.

 

[OrangeCones]

It certainly seems like vastly different water parameters to kill so quickly, but your test results don't indicate that at all. Is there a possiblity that the testing is wrong? Test kits do expire and the 'dip strips' are quite easy to get contaminated and give incorrect readings.

I've always drip acclimated my fish (even from one tank to another in the same room) to help prevent any stress.

 

[Astroman]

Thanks for the thoughts. My test kit was 2 month old API. The only thing I can think of since it happened is that with acute stress they produced ammonia, and died from it. Maybe the Prime I added detoxified the ammonia so my test result was negative. Whatever happened it was an acute poisoning . The Cory's and the one barb are still fine.

 

[Fishman1995]

It seems to me that perhaps alot of poop was made or added to the bag and caused an ammonia spike due to concetrations? Thats the only thing i can think of. Very strange indeed.

 

[OrangeCones]

Maybe the Prime I added detoxified the ammonia so my test result was negative.

Prime binds with ammonia, but the test kit would still show ammonia if present in a detoxified form (ammonium). Any dechlorinator works by reduction, which removes oxygen from the water. But, if it were an overdose of Prime, the fish would show signs of stress in the bag, not once released into the main tank. Quite a puzzle indeed. I'm glad the others are still ok.

 

[rb8jo]

Could it be the temperature? I once moved my orandas to another tank that was in a room under the ac vent and they went into mild shock and I tested the water and it was basically the same then it occurred to me to temp test and there was a ten degree difference.

 

[Astroman]

Temperature was the same. I moved the one surviving barb into the tank (dripped him) without issues. The Cory's are fine.

 

[rb8jo]

I know very little beyond goldfish and apple snails. And considering the responses I got to my posts I must be doing that wrong. So my 10 year old fish kids and I will just sit still and suck our toes and be quiet in our chemical free lives. hahaha.