Tiger barbs die after water change!

[TJ _isme]

the tank had 1 red tailed black shark, 4 yellow lab cichlids, 7 tiger barbs, 2 mystery snails.

don’t under why this happened, the week before last week I did a 50% water change and when I was done All the fish were fine except 1 tiger barb, he was floating around the tank twitching, then 30 minutes later he died. 

The next week I got sick so I did not do a water change,

 

Now today i did a 70% water change and then the multiple tiger barbs do the same thing as the one did a few weeks ago

i dont understand why this is happening and I need help all advice and comments are appreciated 

 

[DBrown918]

Did you make sure to remove chlorine/chloramines first with a water conditioner?  What type of water are you adding?  Tap, RO, well?  If the parameters of the water you are adding are very different than the aquarium water it could have put them into shock and killed them.  You should test the water of the aquarium and what you are adding for a water change for better information.

[TJ _isme]

I added seacham prime midway through the water change so I don’t think the chlorine/chloramines were the problem, 

the water I added was just tap water which is all I have ever used 

the tank had about 1 ppm of ammonia, nitrite is 0 and there was about 80 ppm of nitrate, it was a fairly new tank (only 3 month old and only had fish for 1 month)

now the tank has roughly 0.5 ppm of amonia, 0 nitrite and, 40 nitrate

My tap water and tank water is 7.8 ph and both are fairly hard

[DBrown918]

The ammonia wouldn't cause them to suddenly die that fast.  Something put them in shock.  You were removing ammonia by changing the water, so if anything that would have helped.  It's got to be either chlorine or something was vastly different with the added water.  Is it possible it was a huge temperature swing?  Something was amiss.

[Whitecloud09]

On 5/8/2024 at 4:20 PM, DBrown918 said:

The ammonia wouldn't cause them to suddenly die that fast.  Something put them in shock.  You were removing ammonia by changing the water, so if anything that would have helped.  It's got to be either chlorine or something was vastly different with the added water.  Is it possible it was a huge temperature swing?  Something was amiss.

Temp swing is what I was thinking. Maybe something wrong with your tap if that is what your water is, maybe test tap in all categories. How hard is your water? Gh kh, ?

[TJ _isme]

My water is fairly hard (idk the gh or kh but if it helps the tds is 300)

I don’t think it was temperature, I measure the water to make sure it is the same temp as in the tank before adding it)

[DBrown918]

Then you've got a mystery on your hands brother.  Good luck.  I guarantee you something wasn't right with the added water.

[TJ _isme]

On 5/8/2024 at 9:04 PM, DBrown918 said:

Then you've got a mystery on your hands brother.  Good luck.  I guarantee you something wasn't right with the added water.

Thank you for your help, I am planning to stop with the Lardge volume water changes and now I am just going to do 25% water changes twice a week, the tank is fairly heavily stocked so i think it needs it.