Tiger Barbs All Dead

Sad morning. Last night I noticed one of 11 tiger barbs turning sideways and swimming crazily. He seemed like he lost color and was “shiny”. After dinner proceeded to do a 50-75% water change and saw more tigers following the same symptoms. After the change, 3 had died within that time. By the end of the night 5 total had died. 6 left. I should side note I had 6 originally since the tank cycled and added 5 about two weeks ago, and the first ones to die were all the new ones. Now the 6 originals were left. By morning all were dead. All other fish in the tank have been ok with no signs of death. What is my problem here?

 

Following, because my new tigers have this exact issue...

 

I'm so sorry for your loss. What are your parameters, and can you post a picture of the affected/infected fish?

 

I'm so sorry for your loss. What are your parameters, and can you post a picture of the affected/infected fish?

Unfortunately I’m on my 24 hour shift at the moment so cannot until tomorrow. But I checked parameters before I did my water change last night and they were 0,0,40. Nitrate a little high but that won’t be the problem. And PH 7.6 which isn’t ever changed due to tap water PH.

 

Following, because my new tigers have this exact issue...

If you look at freshwater fish disease there’s a newer post that has symptoms of the disease columaris or however you spell it and it has most of the same issues so that may be the problem. In the post they have all ways to eradicate it.

 

If you look at freshwater fish disease there’s a newer post that has symptoms of the disease columaris or however you spell it and it has most of the same issues so that may be the problem. In the post they have all ways to eradicate it.

Columnaris doesn't kill all fish within 24 hours I'd say.

 

My fish don't have columnaris, for sure.

 

Columnaris doesn't kill all fish within 24 hours I'd say.

With the very long column I read there are different strands and some are slower than others, but some are very rapid and can kill within 24-48 hours, so the column says.