5 Deaths after water change

[FishCow]

Hi,
I've had the same 4 ft planted tank up and running for almost 3 years.Water parameters are handled well by the canister filter and water changes.
I use Seachem Prime when I attend water changes. I've followed the same routine with flawless results.
This morning I woke up to find 5 dead tiger barbs. I can't work out what happened.
The water parameters are all good. TDS 87 , PH 7.0 , nil ammonia or nitrites and < 10 ppm Nitrates. T 25-26c
I live in Canberra, ACT Australia and our water in considered soft.
I have 8 swordtails, a pair of Kribensis and 2 young yoyo loaches and they are all healthy and unaffected by whatever happened.
As I type this, we just discovered two more dead.

Any ideas greatly welcomed.
Regards

 

[gwand34 151]

The water is a little soft for barbs but I doubt that caused the sudden death of five fish.

 

[GaryE]

How long had it been between water changes?

 

[FishCow]

How long had it been between water changes?

2 weeks before the last one I did yesterday.
It's baffling

 

[GaryE]

That is baffling. I asked because sometimes if we have to go a few weeks, we see deaths from a water hange. But not here...

I've seen single species die offs in tanks, where no other species suffered. They are odd, and possibly viral. But they push us into the realm of guessing.

 

[VioletThePurple]

2 weeks before the last one I did yesterday.
It's baffling

Check your city's local water quality report

 

[FishCow]

Check your city's local water quality report

Yeah, nothing as far as drinking water goes. Nothing unusal. Thanks

 

[emeraldking15 66]

And sometimes no logic explanation can be found...
And if I look at your water parameters, they're not really excessive for tiger barbs. Maybe it's something that's only contageous to tiger barbs. Maybe a smear of the mucous membrane could tell us more.

 

[FishCow]

And sometimes no logic explanation can be found...
And if I look at your water parameters, they're not really excessive for tiger barbs. Maybe it's something that's only contagious to tiger barbs. Maybe a smear of the mucous membrane could tell us more.

IDK. maybe I filled to tank too quickly this time, trapped nitrogen. Pulling at straws. I'll just chalk it up to bad luck and hope no more fish die

 

[emeraldking15 66]

IDK. maybe I filled to tank too quickly this time, trapped nitrogen. Pulling at straws. I'll just chalk it up to bad luck and hope no more fish die

Hope you'll find out the cause of it soon. But again, sometimes it's something contageous that will only harm a specific type of fish.

 

[Innesfan33 17]

Are there any tiger barbs left and how long have you had them?

 

[FishCow]

Are there any tiger barbs left and how long have you had them?

There are 7 left and they seem fine. I think it's been only just over 2 years - they should live 5+ from what I've gleaned.

 

[FishCow]

This is just pure speculation, but after researching it seems there was a tragedy of user errors.
1. I filled the tank using a submerged jug and a hose going into the jug. Apparently this causes gases to form under pressure. I think my fish got "the bends" ?
2. Water was tepid, but maybe this time too warm = less dissolved oxygen?
3. Apparently, late March in Canberra the water supply lines are "slugged" with extra chlorine for maintenance. I didn't test for chlorine and I didn't dose the tank with Prime until after I had already filled the tank.
At least I can test the tap water for chlorine to see if this was actually an issue.

I don't know to be very honest, but I'll change the way I do things for the future and minimize user-error.
I presume the other species in the tank are just more robust and managed to get through unscathed, the Moss Green Tiger Barbs . . . not so much.
Thanks for the help

 

[GaryE]

The city water management could be a thing. I'm in Canada, but every Fall, the pipes get an overnight treatment that's not only heavily chlorinated, but descales the water supply system. If you do a water change right after, fish die. The water comes out greyish, and is full of debris for a very short but intense time.

I've done water changes after twice in many years, and didn't catch it the first time. It killed some species and not others. I didn't think of it in this situation because in my mind, it's seasonal and climate related. That doesn't make sense when I think more seriously, as water systems are water systems.

 

[gwand34 151]

My well water in February had 335 ppm TDS. Today the TDS is 450 ppm. What the heck caused an increase of 115 ppm? I’m afraid to find out.