Fish-in Cycling

Just for the record. I believe that the best thing that could happen to this thread is for it to be completely deleted. The advice is mostly so far off the mark as to almost insure that fish are harmed or killed. For sure the odds are good that following it will shorten the lived of all the fish involved even if it doesn't outright harm of kill them.
 
In a fishless cycle one should try to be doing as few water changes as possible.
 
If you do not know the difference between NH3 and NH4 and what part of total ammonia they might be, you should simply not even think about doing a fish in cycle. If you do not know about nitrite and chloride, the same applies.
 
For close to two years I have been challenging tos who insist that massive water changes are needed any time total ammonia reaches .25 or .5 ppm to provide a single shred of scientific research to support this. To date not a single person has been able to do so. On the other hand I have provided links to study after study that supports the opposite view.
 
Sigh......
 
Please, do not try to cycle a tank with fish. If you have started, either add enough viable bacteria to get the tank cycled as close to instantly as possible or else remove the fish and complete the cycle without them.
 
So my question is, is nitrate good for the fish? @ ammonia and nitrite bad?
 
Nitrate is not good for fish, no, but they can tolerate much higher levels of it than they can of ammonia or nitrite.
 
Ok so what would you say the maximum limit for nitrate nitrite and ammonia can be in a south american cichlid tank can be
 
Ammonia and nitrite should both be at zero. Nitrate can go up to around 60PPM, or 20PPM above what's in your tap water, whichever is the lowest.
 
But some South American fish can be less tolerant of nitrate, such as discus and German blue rams.
 
eaglesaquarium said:
But some South American fish can be less tolerant of nitrate, such as discus and German blue rams.
Grrr, I'm not on the ball today.

Thanks for clarifying that, eagles.
 
Ok so just a water change can change those level and would you recommend sucking up nastiness from rock or just strictly changing out water?
 
Bear in mind that nitrate studies/research are done using the nitrogen scale. We are testing using the total ion scale. To convert from the nitrogen scale to the ion scale you multiply by 4.43. In the USA the amount of nitrate in drinking water is limited to 10 mg NO3-N/l. On an API test kit that would be 44.3 ppm.
 
The next thing is, I can go on Google Scholar and find endless studies on ammonia toxicity, I can find plenty of good ones on nitrite as well. Trying to find studies on nitrate relative what goes into our aquariums is a real challenge. I can find more information on nitrate and inverts than on fw fish. But here is an abstract i did find.
 
 


Abstract

Increasing concentrations of nitrate in surface water and groundwater are becoming a worldwide concern, yet little information has been published on toxicity of nitrate to common organisms used for toxicity testing. The acute and chronic toxicity of nitrate (NO3-N) to Ceriodaphnia dubia, Daphnia magna, and Pimephales promelas was investigated in 48-h to 17-d laboratory exposures. The 48-h median lethal concentration (LC50) of nitrate to C. dubia and D. magna neonates was 374 mg/L NO3-N and 462 mg/L NO3-N. The no-observed-effect concentration (NOEC) and the lowest-observed-effect concentration (LOEC) for neonate production in C. dubia were 21.3 and 42.6 mg/L NO3-N, respectively. The NOEC and LOEC values for neonate production in D. magna were 358 and 717 mg/L NO3-N, respectively. The 96-h LC50 for larval fathead minnows (P. promelas) was 1, 341 mg/L NO3-N. The NOEC and LOEC for 7-d larval and 11-d embryo-larval growth tests were 358 and 717 mg/L NO3-N, respectively. Additional exposure of breeding P. promelas and their fertilized eggs to nitrate did not increase susceptibility further. The LC50 values for all species tested were above ambient concentrations of nitrate reported for surface water. However, the LOEC for C. dubia was within the range of concentrations that could be found in streams draining areas under extensive agricultural cultivation.
from http://onlinelibrary.wiley.com/doi/10.1002/etc.5620191211/abstract;jsessionid=C382FC822428F8B6679F7312DF613CF8.f04t01?deniedAccessCustomisedMessage=&userIsAuthenticated=false
 
Here is one study with numbers for an assortment of inverts and fish. When going through it remember to multiply all the nitrate levels listed by 4.42 to make them equivalent to what you would read on an API type test kit. http://yaphankcivic.org/uploads/Nitrate_Toxicity_to_Aquatic_Animals. Many of the numbers will amaze you.
 
So, in a nutshell, the highest level where there was no observed damage to the fish of any species in the study was approximately 80 on the API ion scale.
 
My 2nd link seems to be incorrect- here it is again http://yaphankcivic.org/uploads/Nitrate_Toxicity_to_Aquatic_Animals.pdf Please note in reading this that all of the fish involved were either eggs, fry or fingerlings.
 
Eagle, if you are referring to the quote part, that was for water fleas, not a fish, and the number was 94 ppm for the NOEC (API equaivalent). That study looked at the water flea, daphnia and one fish. For that one fish the NOEC number was in the 1,000s depending on how many days "The NOEC and LOEC for 7-d larval and 11-d embryo-larval growth tests were 358 and 717 mg/L NO3-N, respectively. Additional exposure of breeding P. promelas and their fertilized eggs to nitrate did not increase susceptibility further."
 
But note it also stated "The 96-h LC50 for larval fathead minnows (P. promelas) was 1,341 mg/L NO3-N."  This means that level of nitrate it took for a 4 day exposure to kill 50% of the fish on an API test would read 5,940 ppm.
 
The second study is more in depth. However, it is important to realize that these studies cover a variety of fish. It is well know that salmonids are very susceptible to nitrogen compounds, But who keeps salmon or trout in their tanks? When looking at most fish the numbers for nitrate are pretty high. Bear in mind a lot of the research on this topic often deals with wild fish in natural habitats. And most of these fish are not the ones we find in tanks.
 
I still believe in an established tank, one that is not clearly overstocked, regular weekly water changes of 35% - 50% should hold nitrate levels where they are not a concern. What still amazes me is, despite knowing about all the problems with nitrate test kits, how many people simply accept the test results without question.
 
Well, my number was in reference to the lowest value that would be toxic to a specie, any specie, and would correspond to the API test kit - which measures: 0, 5, 10, 20, 40, 80 and 160 ppm, if I recall correctly.
 
 
In other words, trying to find a 'rule of thumb' which for me would be keep your nitrates below 80ppm.
 
In that case 80 ppm wont due it when you include species not found in tanks, In fact, that 10 mg NO3-N/l wont do it either. The number is saw to protect every conceivable fw creature (not just fish but amphibians and bugs) is 2 mg NO3-N/l which on the API test is just under 9 ppm. This would mean 80 ppm is not "safe" either. But again, most of the very sensitive critters you can find data for relative to nitrate will not be found in home aquariums.
 
But look at that article, all of the really sensitive species we don't keep like Rainbow trout, Chinook salmon and the Blackspotted Cutthroat Trout. They are bugs and amphibians you can barely find info on in some cases. One is the Northern leopard frog another the common toad. These are not things almost anbody keepes in their aquarium. But, if one has a setup for keeping a salmon or a trout, or these amphibians, then I assume one would know the relevant nitrate numbers for keeping them safe as well as a ton of even more important things.
 
But here is the thing about all this. Nitrate is sort of like NH4 in that it does not easily pass into fish. When it does, it works like nitrite to make the blood unable to carry oxygen. This means the symptoms of nitrate problems are just like nitrite. So it become obvious in a cycled tank if nitrate is the issue since there should be no nitrite.  While I have never seen it stated outright that salt (chloride) will also help with nitrate, I assume it probably will do so based on the fact that salt water fish seem to have a higher tolerance level for nitrate than do fw fish. This is similar to the case with nitrite where the reason is the definitely the salt.
 
If you have a normally stocked tank, weekly water changes will usually insure nitrate is never an issue. If you have an over stocked tank, you may have to do them twice a week. I have never used a nitrate test to make any decisions about what to do in a tank with one exception. That was a high light, co2 added planted tank that left 0 nitrate in a tank by the end of a week. I needed to know that I had 0 and should be adding nitrate to that tank after a water change.
 
"any specie" was not the right term... I suppose a better descriptor would have been 'most readily available common specie, fish, or otherwise, not labelled as sensitive'.  This would exclude discus.

Based on the second article you linked, you may very well be correct regarding the nitrate-salt connection, given that it references 2 mg/L for NH3-N for freshwater sensitive species, and 20 mg/L for NH3-N for marine species.
 
But, the downside is that the article is related to 'inverts' not fish. :/
 
I really wish I'd seen this before doing my aquarium with poor fish in :( but it does make sense to me so if I had seen this I would totally have understood it :)
 

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