Twotankamin And Nitrite

[the_lock_man]

As a word of advice. The way nitrite works to suffocate fish can be mitigated in an emergency by adding salt to the water. The chloride binds to the same places the nitrite would. When the salt binds to these sites, the nitrite can't. Of course salt can cause other issues as it changes the TDS and many fish and plants do not handle it. It is important is one uses salt in this fashion that it be removed from the water when it has served its purpose. The way to remove it is via water change.

 
Fascinating. Flesh this out a little for me, please - the chloride binds to what - something in the water?
 
As I understood it, nitrite binds to the haemoglobin in the fish's blood, preventing oxygen from doing so, yes? If the chloride does this too, then it would be no different, the fish would still be suffocating, so you can't mean that.
 
Cheers.

 

[DrRob]

It does indeed, and you're going to ask me for references now, which I'm going to have to go dig up, but as I understand it the chloride and the nitrite are picked up by the same osmoregulation system in the fishes gills, so salt competitively competes with the nitrite to be taken up, which slows the level of nitrite entering the blood and stops the nitrate from clogging up the pathway.

 

[JCorvinus]

if i understand this correctly , the nitrite bonds to the blood , where as  the cloride , slows down absorbion through the gills , making them less effective , and less able to suck up the poisens, 
 
would i be correct also in thinking that this could effect the bio filter if added directly to the tank , or would it be a dipp treatment for a fish 
too much tap water could suffocate the fish as well over a longer period of time 

Dr Rob please confirm if you agree 

 

[the_lock_man]

Two-T PMed me a couple of research papers which basically said what Rob said.
 
The more easily-understood one said that to be most effective, the concentration of salt needed to be 9-10 times that of nitrite.

 

[TwoTankAmin]

On the topic of ammonia and nitrite and what might be a good fish for fish in cycling, we always hear zebra danios are good.
 
Also keep in mind what we so often read in response to somebody reporting .25 or .50 ppm of Nitrite on and API or similar kit in and why it should be done.....
 
I was surfing Google Scholar, as is my wont, and stumbled across a mind bending piece of research. I will give brief description. The researchers were interested in testing the effects different levels of nitrite have on the growth of young zebra danios (a few weeks old) over the short term, defined as 28 days. I will give two helps here:
1)  They are measuring NO2- (not NO2-n). So the scale is the same as on an API, or similar, test kit.
2)  1 mg·l-1 = 1 mg/l = 1 ppm.
 
Now read away and then tell me what you think. It is not real long (barely 5 pages including some tables) nor hard to understand for the most part http/actavet.vfu.cz/pdf/200877030455.pdf

 

 

[eaglesaquarium]

So, if I am reading this right, 28 days exposure to nitrite levels as high as 130ppm (!!!) resulted in not a single fatality amongst the zebra danios, which were 20 days old at the time of their first exposure to the specific nitrite concentration they were exposed to.
 
I knew zebra danios were tough little fish, but that's extreme.  I'm curious as to what implications that might have beyond danios.

 

[DrRob]

Now that paper is fascinating.
 
What I find most interesting is that, at levels much lower than that, my fish die (fortunately not for a long time, but it has happened).
 
To me, this suggests that nitrite isn't the entire problem, just what we can measure. The fundamental difference between what happened in that paper and what happens in our tanks (or hopefully doesn't) is that they added known concentrations of nitrite from an external source (which, to be fair, fits what they were trying to study) rather than have a system failure of some kind that results in nitrite rises.
 
As we so frequently tell people about rising nitrate levels being simply an indicator of need for water changes, rather than reducing that specific test result being the goal of regular maintenance, I do wonder if our aquarium based problem is related to the other things that arrive with the nitrite itself that result from a biofilter failure or overload, rather than simple nitrite toxicity.
 
Either that of zebra danios are weird, but that, I suspect, is probably also an issue.

 

[eaglesaquarium]

I'm wondering if nitrite exposure AND ammonia exposure, or nitrite exposure right after ammonia exposure might be the issue in the hobbyist tank.
 
 
 
As for zebra danios - my school does 'ecocolumns' all the time (which I hate by the way) and last fall there was a zebra danio that was left in an uncycled, unfiltered, 1 gallon box with approximately 1 Liter (if that) water in it, with a ton of excess food sitting in that tank.  This danio sat in there for over 2 weeks like that before I found out about it.  It had a sunken abdomen, red gills, etc.  I nursed it back to health in a matter of a week in an uncycled 10 gallon tank I happened to have available.  It bounced all the way back to be 'healthy' and I moved it on to someone else's tank after I was satisfied with its condition.  So, long story short - zebra danios are ridiculously tough fish!

 

[TwoTankAmin]

It is never simple. I can show other studies where different species were 50% dead in 96 hours of exposure to NO2 at levels way below the lower in the that danio study. And then I can find others that indicate the fish handle nitrite better.
 

 
J Environ Biol. 2002 Apr;23(2):147-9.

The toxicity of ammonia, nitrite and nitrate to the fish, Catla catla (Hamilton).
Tilak KS, Lakshmi SJ, Susan TA.


Source
Department of Zoology, Nagarjuna University, Nagarjunanagar-522 510, India.



Abstract

The acute toxicity of unionized ammonia; nitrite and nitrate to the Indian major carp Catla catla (Hamilton) was determined using static and continuous flow through systems for 24 hours. The median lethal concentration (LC50) values for 24 h of ammonia (NH3-N), nitrite (NO2-N) and nitrate (NO3-N) were 0.045 mg/l, 120.84 mg/l and 1565.43 mg/l in static test respectively and were 0.036 mg/l, 117.43 mg/l and 1484.08 mg/l in continuous flow through test respectively.

from http/www.ncbi.nlm.nih.gov/pubmed/12602850
 
That study wanted to find out whats levels it took to kill half the fish inside 24 hours. Now I know that this doesn't tell us much about lower levels and longer time frames. But it is also telling us that 120.84 ppm of nitrite could only kill half the fish in a day. So what would say .25 or .5 ppm which is 1/483 - 1/241 less concentrated?
 
I think what I am seeing here is a very good explanation for one of the two most important considerations when doing a fish in cycle- selection of the fish to be used. Once of the central precepts of fish in cycling is to choose a very few hardy fish. And hardy clearly means the ability to survive both the ammonia and nitrite that are typical in the cycle. It is the very few part that is the other key. Very few means maximum levels reached for ammonia and nitrite will be lower. That part is common sense, of course.
 
I have always felt that a lot of what I read on fish sites regarding what to do when ammonia or nitrite levels on the typical kits show .25 or .5 ppm. If you are doing a fish in cycle with the proper number and types of fish, the answer is nothing, imo. My reasons are simple- the right fish can handle such levels and then the more one lowers ammonia and nitrite levels, the slower cycling goes. The problem is cycling will not take place without some levels of these two things present. So changing water a lot doesn't remove them, it merely lowers the concentration. And that opens up a whole new discussion, what effects do extended periods of exposure do those lower levels have vs higher levels but for a much shorter period? That is the trade off to consider when deciding when to change water during a fishless cycle because ammonia and/or nitrite levels reach any given point. What exactly is the difference between exposing a fish to say .25 - .50 ppm of ammonia or nitrite for 2 weeks vs exposing them to .10 ppm for 6 or 8 weeks or more?
 
Somewhere between the warning to change a lot of water immediately when you see .25 ppm during a fish in cyle and the ability of some fish to handle these levels and more for some short period of time lie the facts. However, I am convinced of one thing for sure. When giving advice on fish in cycling, it is essential to make it very clear what types and how many fish to use.

 

[eaglesaquarium]

I think the easier answer is just: "Do it fishless." 

 

[TwoTankAmin]

 I agree. But not everybody will do this for a variety of reasons. And for those folks who do opt for the fish in route, its almost more important that they do it properly than in the case of fishless. For such folks, I really think explaining the best way is more important than showing fishless cyclers why they should use less ammonia. In one case fish may be killed in the other the fish keeper may be frustrated. Rumor has it that is is easier to become unfrustrated than undead.

 

[eaglesaquarium]

Link?

 

[TwoTankAmin]

In my continuing journey to satisfy my own curiosity on such subjects I have come across a really interesting paper on nitrite toxicity to fish. It is one of the better ones I have found. Before giving the link I would like to offer a couple of quotes and comments:
 

 
The literature dealing with long-term toxicity of sublethal nitrite concentrations corresponding to Review Article Vet. Med. – Czech, 50, 2005 (11): 461–471 466 10% of 96hLC50 suggests that such a concentration should not be detrimental to freshwater fish. Neither growth suppression nor tissue damage was observed (Wedemeyer and Yasutake, 1978; Colt et al., 1981).

 
What this is saying is that the level of nitrite that will kill 50% of the fish within 96 hours when at 10% of that concentration should not be harmful to fish. This is important because almost all studies tend to look at what kills fish not what just might cause lesser or reversible damage.
 

 
4.2. Water quality
 
4.2.1. Chloride

Since 1977 nitrite toxicity has been known to depend greatly on the salinity of the water in which the nitrite exposure took place (Crawford and Allen, 1977). Mortality in seawater occurred at nitrite concentrations 50 to 100 times higher than in fresh water (Crawford and Allen, 1977). The effect of chloride on the toxicity of nitrite is now known to be so great that experiments in which chloride concentrations are not documented are of very low value because they cannot be meaningfully compared with the results of other studies.

 
What this is saying is that chloride has such a great affect on determining the potential for damage of nitrite that it must be measured an taken into account when researching nitrite toxicity.  Failure to do this make such research virtually worthless.
 
Lastly, I would point out that most of the nitrite measurements in the study are made using the NO2-N scale. On this scale 1 ppm of NO2-N will read 4.4 ppm when tested on the total ion measuring hobby kits such as the API one.
 
Now, for those so inclined http/www.agriculturejournals.cz/publicFiles/61325.pdf

 

[eaglesaquarium]

That first quote is VERY interesting to me... the concern I've had was long-term issues with lower level concentrations.  But, apparently I've been quite baseless in this assumption.