Nitrites Through The Roof...

Lily44

Member
I'm brand new to fish-keeping. I have a five gallon tank with three (Glo) danios. Yes, I know this is too small for them, but I can't get a bigger tank right now, so I'm trying to just take care of them best I can. But I cannot seem to get my nitrites down... I've changed 20% of the water everyday for a week, I added media to the filter, I bought Quick Start and Stress Zyme. Nothing is working.

Now I have one of my fish at the very top, swimming back and forth at the water line. He has a distended stomach and what looks like flipped out scales on the bottom of his stomach. The other two zip around and chase each other.
 

Inactive User

Member
How high is "through the roof"? Nitrite is quite toxic.

As a point of comparison, the nitrite LD50-96hr for cardinal tetra (that is, the lethal dose of nitrite required to kill 50% of a population of cardinal tetra over 96 hours) is 1.5 ppm and mortality is induced with as little as 0.25 ppm (de Oliveira et al., 2008).

The behaviour of one of your fish suggests nitrite poisoning. I would recommend doing several large (50%) water changes one right after the other to bring nitrite to below 0.25 ppm. In addition, I would suggest dosing aquarium salt: the clinical literature indicates 50 ppm salt (1 teaspoon - 5 grams - per 20 gallons of tank water) is sufficient to inhibit nitrite toxicosis in freshwater fish (Noga, 2010).
 

coralbandit

Member
^^^ +1 ^^^
Easiest to just change water as mentioned . The % you change is the % the nitrite will be removed. So if you are 2.5ppm a 50% change will get you 1.5 ,then the next 50% will get you .75 and so on. Nitirte causes more damage for most fish then ammonia in same ppm .
This also is the one time IMO to use salt . This is what it treats and not just aggravates.
 
  • Thread Starter

Lily44

Member
I only have the test strips (I ordered a kit, has not arrived yet) and nitrites and nitrates are hot pink, which says nitrates 160-200 ppm, and nitrites 5-10 ppm. I did two two-gallon changes after reading what you said. I don't have salts, but I'll be getting some. Thank you so much for replying!
 

coralbandit

Member
2 gallons is a good start. That should have lowered the nitrites to 3-6ppm and the nitrates to around 100.
If you have enough de chlorinator do another 2 gallons and then another later tonight or tomorrow.
Do your best to match temp of new water.
 

Inactive User

Member
No problem at all! On a worst case scenario, say your nitrite is 10 ppm. To reduce it to <0.25 ppm, it would take 6 separate 50% water changes.

Again, I would test after every second water change just to get an idea of where your nitrite may be to determine whether further water changes are necessary.
 

Skavatar

Member
sounds about right, my tanks when going through the nitrite phase was in the 6-8 ppm range for 3 weeks even with 50% water changes.

do you have Seachem Prime? it is a life saver.
 
  • Thread Starter

Lily44

Member
Following up...

I've done four two-gallon-each water changes. The water is crystal clear now.

API test kit arrived:

Ammonia: 0 (maybe 0.25)
Nitrates: 20-40 (not sure which one)
Nitrites: 2-5ppm (it's a dark purple, so I don't know if that means its higher?)

My sick fish is struggling, but he's holding on. He's gone from staying at the surface the whole time to now staying at the bottom, either hiding in the cave or under the plant.
 

Inactive User

Member
Lily44 said:
: 2-5ppm (it's a dark purple, so I don't know if that means its higher?)
You need to more water changes to reduce nitrite to (ideally) 0.25 ppm.

I would (and note that I am not a veterinarian) interpret the behaviour of your fish as an indication of methaemoglobinaemia ("nitrite poisoning"): nitrite poisoning prevents red blood cells from effectively transporting oxygen and releasing it to tissues.

You can add 1 teaspoon (5 grams) aquarium salt per 20 gallons of tank water. This is the only effective drug treatment noted in the clinical literature for nitrite/nitrate poisoning in fish (Noga, 2010).

There is no clinical evidence for Seachem's claims that Prime is capable of "detoxifying" nitrite or nitrate. It is purely anecdotal, and there is better assurance in using what is known to be effective in the clinical literature (i.e. water changes, salt).
 

Skavatar

Member
the API chart is not very definitive. once nitrites get into the purple/dark purple. can't tell the difference between 1ppm, 2ppm, or 5ppm. and 5ppm is the max, so your nitrites could be more than 5ppm. I used half tank water and half tap and still got a reading in between 2-5ppm. this went on for 3 weeks in all 3 of my tanks. even after doing 50% water changes. my own experience was that my fish stopped dying after I started using Prime.
 

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