Nitrate Killing Fish

[mark7616]

My mother in law has just been told by her lfs that her nitrate is off the scale and that is what has killed 6 of her mbuna over night now when i asked her what her nitrate was she told me 20 now the lfs said it was off the scale and that is whats done it.
Now i cant check it myself but the 3 synodontis are fine its just 6 mbuna that died over night now even if the nitrate was off the scale would it kill that many fish in 12 hrs i didnt think it would what do you think?

 

[trout750]

I would say that a nitrate of 20 is fine and do not beleive this is what killed them, it could be a lack of oxygen due to the hot wheather lately, this will bring oxygen levels down, is the outlet on the filter breaking the water surface, if not i would position it to do so as this should help.

 

[mark7616]

There is ample oxygen in the water but as i said even if the nitrate was off the scale it wouldnt kill 6 mbuna in 12 hrs would it

 

[trout750]

it shouldnt do no, i had problems with my nitrate a few months ago, it was reading 60 and my fish didnt show no signs of stress, it was at this level for a good 2 weeks and i had no deaths in the tank.
good luck with finding out the cause of death,
just a thought, are there any pairs breeding at the moment, if so they can become agressive to the point of killing. but 6 fish seems like a lot if that was the case. was there anyone i the house when this happened, the reason i ask this is because there might have been a power cut in the area that you may not have been aware of, causing oxyegen levels to plummet. sorry i cant be of anymore help. good luck