nitrites rising in discus tank

[marfa59]

The nitrites in my tank have risen, probably after adding new discus. I am doing water changes to keep the nitrites down. So far they have risen to .5, going down to .25 after a water change. I have added salt after a water change. My question is what amount of nitrites is lethal for discus (what number should make me panic)?

[marfa59]

thanks Graham.
How often do I put in the salt?

[rickztahone]

If you were not doing any water chnages then you would only add it the once. But when you're doing water chnages you have to add back the correct amount salt for the amount od new water being added.

So if you do a 50% water change then you would add back 50% of the salt.....

BTW any salt can be used other than marine mixes

excluding Epsom as well, regular table salt will do

[GrillMaster]

I am just curios why you didn't cycle the tank before you added the discus. :inquisitive:

[mmorris]

I would expect the nitrites to rise a bit in a cycled tank after increasing the bio-load. The bacteria will catch up quickly.

[marfa59]

Grillmaster,
I did cycle the tank before putting in the discus. I cycled for 35 days. Ammonio and nitrites went up then both went to 0, nitrates ended at 10. Let it stay at these numbers for a couple of weeks before taking the tetras that were in there to live in an aquarium at a local elementary school and putting in my discus. The breeder said I would have a spike in nitrites initially because I was adding bigger fish. I just wanted to know how high the discus could tolerate.

[Jhhnn]

From what I've been able to read, .5ppm is "irritating" to fishes' gills, and 3-5ppm or above are lethal over time. That's w/o adding salt.

My own 120gal tank was poorly cycled when I received my discus from Kenny- but with daily 50% water changes, nitrites never went over 1ppm, and I never added more salt that 2 tbsp/ 50 gal of aged water w/~ 50% extra prime...

The fish were fine the whole time- vigorous, healthy, hungry- no lack of color or darkening, either...

I did inexplicably lose one fish, who bloated up and perished over a period of 24hrs... I don't think that was water related, at all...

Even now, 2 months later, tank water sometimes shows a small level of nitrites- it's tough for my old eyes to differentiate the readings on the the comparo strip below .25ppm...

[Don Trinko]

when you cycle a tank (fish or fishless) you cycle for a specific bioload. When you add more fish than cycled for you get a mini cylcle while the bacteria builds up to the proper level for the new bioload.
If you cycled with teras (small fish) and then added Discus (big fish) you probably exceeded the bioload created by the tetras.
It is always a good idea to have some chemicals around to nutralize any possible spike in ammonia or nitrites.
I have done this when adding fish, cleaning the filter in tap water and several other ways.. All of this IMO; Don T.

[marfa59]

Thanks everyone. Just checked my nitrites and they are almost 0 again. I can breath!! This makes a beginner discus owner nervous!!!! I sure am enjoying them, what beautiful creatures!!

[GrillMaster]

Gotcha! I guess I didn't read far enough into it. A mini cycle with the excess bioload will end pretty quick as the others stated. Glad ya got it sorted. :)