Rummy Nose Tetras Dying

[Seal36]

I had 6 rummy nose tetras in a 110litre tank. I had them for 3 weeks and on Monday I added 4 more to take there numbers to 10. I got them from the same fish shop and from the same tank as the other 6. This morning I woke up to find one rummy dead behind the filter and another one in a death spiral which then died a few minutes later.

The remaining 8 rummies have bright red noses and are still shoaling and acting normal and I was wondering if it was a coincidence or if there could be an infection in the tank. I have had no other species of fish die and all the other fish in the tank look perfectly healthy. Just thought it was a bit odd about them dieing. Have just tested the water before posting this.

The water parameters are
Nitrate 10
Nitrite 0
General hardness 8d
Carbonate 6d
Ph 7.4
Chlorine 0

 

[the_lock_man]

It would appear from the results you've posted, that you are using paper test strips, which are not spectacularly reliable. Furthermore, they don't have an ammonia test, which is the first thing I would ask you for.
 
How did you cycle the filter in the tank?
How do you maintain the filter and water ()in terms of water changes, filter changes, etc.)?

 

[Seal36]

Yes I do use paper strips

The tank has been set up for 14 years so the tank has defiantly cycled

I do 2 water changes a week 10-25% on Wednesday and 50% on sat

 

[Ninjouzata]

Did you happen to change the filter media or something? What are the other tankmates? How did you acclimate them?
I hope someone can figure this out for you. I've had lots of rummy deaths, showing no symptoms and water parameters were the way they should be (0 ammonia, 0 nitrite).

 

[Seal36]

No I did not change the filter media, other tank mates are kribensis that have just started spawning but the rummies know to stay well clear of them even if they are not spawning. I know it's not the best way to acclimatise them but I put the bag in the water for 15 min and then add some tank water into the bag and let it sit for another 15 min and they put the fish in. This is how I acclimatise all my fish and with the first 6 I did it the exact same way and had no problems