How long does fish need to adjust low salinity to normal salinity

[Lasse]

That would equate to a total NH3-N concentration of 8.5 mg/l

What are you talking about?

un-ionized ammonia is NH3 or the gas NH3.
Ionized ammonia is NH₄⁺ - the ion from the gas NH3.
NH3-N is the N part of the gas NH3 or the N part of the un-ionized ammonia
NH₄⁺-N is the N part of the NH₄⁺ or the N part of the ionized ammonia.

"0.57 ppm of un-ionized ammonia" at a pH of 8.1, that would equate to a TOTAL ammonia level of 8.5 ppm - and that's unheard of!

Maybe you have not heard about it but they discover issues with the gills (sub lethal damage) at this concentration. Its not a LC50 figure

If the unionized ammonia expressed as NH3-N is 0.57 - the unionized ammonia expressed as NH3 is 0,57*1,21 = 0,69 mg/L NH3. This experiment was done in 27 ppt saltwater, 27 degree C and a pH of 8.15. In this case - back calculation give a total ammonia (NH3+NH4 or ammoniac+ammonium) of around 7,6

was your ammonia chloride dose that high?

Its a strange question because in the methods the authors state - my bold

0.23 ± 0.02, 0.57 ± 0.03, 0.97 ± 0.06, 1.05 ± 0.06, 1.22 ± 0.05 and 1.63 ± 0.14 mg/L NH3-N obtained by adding ammonium chloride

Total ammonia nitrogen (TA-N) and nitrite were measured according to Grasshoff et al. (1999) and Aminot and Chaussepied (1983). Un-ionized ammonia (NH3) concentrations were calculated following TA-N, and temperature, salinity and pH values following the equations of Ostrensky et al. (1992), adapted from Whitfield (1974) and Bower and Bidwell (1978).

Apparently - they have add so much ammonium chloride it was needed to get 0.57 mg/L NH3-N. Note that 0.57 mg/L NH3-N is not with in the LC but they could show gill lesions

Once again
un-ionized ammonia is NH3 in British English even named ammoniac
Ionized ammonia is NH₄⁺ - in British English even named ammonium
Total ammonia is the sum of NH3 and NH₄⁺ or in British English ammoniac+ammonium

Is there a -N in the the formula - it means that the mg/l refers to only the N part of the subject. If you have NH3-N - you need to multiply with 17 (mol mass NH3) divided with 14 (mol mass N) = 1,21 if you want to express it as NH3

Most important is that their findings of LC50 is well in line with other similar investigations of salt water fish there the LC50 96h value can vary from around 0.5 up to 2-3 mg/L NH3-N for LC50 96 H (4 days)

Sincerely Lasse

 

[Jay Hemdal Verified Community Expert]

What are you talking about?

un-ionized ammonia is NH3 or the gas NH3.
Ionized ammonia is NH₄⁺ - the ion from the gas NH3.
NH3-N is the N part of the gas NH3 or the N part of the un-ionized ammonia
NH₄⁺-N is the N part of the NH₄⁺ or the N part of the ionized ammonia.




Maybe you have not heard about it but they discover issues with the gills (sub lethal damage) at this concentration. Its not a LC50 figure

If the unionized ammonia expressed as NH3-N is 0.57 - the unionized ammonia expressed as NH3 is 0,57*1,21 = 0,69 mg/L NH3. This experiment was done in 27 ppt saltwater, 27 degree C and a pH of 8.15. In this case - back calculation give a total ammonia (NH3+NH4 or ammoniac+ammonium) of around 7,6


Its a strange question because in the methods the authors state - my bold




Apparently - they have add so much ammonium chloride it was needed to get 0.57 mg/L NH3-N. Note that 0.57 mg/L NH3-N is not with in the LC but they could show gill lesions

Once again
un-ionized ammonia is NH3 in British English even named ammoniac
Ionized ammonia is NH₄⁺ - in British English even named ammonium
Total ammonia is the sum of NH3 and NH₄⁺ or in British English ammoniac+ammonium

Is there a -N in the the formula - it means that the mg/l refers to only the N part of the subject. If you have NH3-N - you need to multiply with 17 (mol mass NH3) divided with 14 (mol mass N) = 1,21

Most important is that their findings of LC50 is well in line with other similar investigations of salt water fish there the LC50 96h value can vary from around 0.5 up to 2-3 mg/L NH3-N for LC50 96 H (4

What are you talking about?

un-ionized ammonia is NH3 or the gas NH3.
Ionized ammonia is NH₄⁺ - the ion from the gas NH3.
NH3-N is the N part of the gas NH3 or the N part of the un-ionized ammonia
NH₄⁺-N is the N part of the NH₄⁺ or the N part of the ionized ammonia.




Maybe you have not heard about it but they discover issues with the gills (sub lethal damage) at this concentration. Its not a LC50 figure

If the unionized ammonia expressed as NH3-N is 0.57 - the unionized ammonia expressed as NH3 is 0,57*1,21 = 0,69 mg/L NH3. This experiment was done in 27 ppt saltwater, 27 degree C and a pH of 8.15. In this case - back calculation give a total ammonia (NH3+NH4 or ammoniac+ammonium) of around 7,6


Its a strange question because in the methods the authors state - my bold




Apparently - they have add so much ammonium chloride it was needed to get 0.57 mg/L NH3-N. Note that 0.57 mg/L NH3-N is not with in the LC but they could show gill lesions

Once again
un-ionized ammonia is NH3 in British English even named ammoniac
Ionized ammonia is NH₄⁺ - in British English even named ammonium
Total ammonia is the sum of NH3 and NH₄⁺ or in British English ammoniac+ammonium

Is there a -N in the the formula - it means that the mg/l refers to only the N part of the subject. If you have NH3-N - you need to multiply with 17 (mol mass NH3) divided with 14 (mol mass N) = 1,21 if you want to express it as NH3

Most important is that their findings of LC50 is well in line with other similar investigations of salt water fish there the LC50 96h value can vary from around 0.5 up to 2-3 mg/L NH3-N for LC50 96 H (4 days)

Sincerely Lasse

Lasse,

You wrote a lot there, but didn't address the issue that I have with this paper. Let's look at one simple conclusion from their abstract:

They state that the 24 hour LC50 for clownfish was 1.06 mg/l un-ionized ammonia. They state that their pH was 8.15

By my rough figuring, that gives a TAN of about 9 to 10 mg/l! I have a strong suspicion that although they wrote "un-ionized NH3" they truly meant TAN. If you substitute TAN for all of their numbers, it lines up quite well with what I empirically know to be true - a TAN of from 0.8 to 1.5 mg/l at marine pH levels is dangerous for fish - full stop, end of story.

My only mistake was using the term "total NH3-N" instead of TAN. They did not use the term TAN in their article, so I wanted to try and explain it by saying that. I also translated my letter into Portuguese in case English might have proven a barrier.

 

[Lasse]

a TAN of from 0.8 to 1.5 mg/l at marine pH levels is dangerous for fish - full stop, end of story.

My only mistake was using the term "total NH3-N" instead of TAN. They did not use the term TAN in their article, so I wanted to try and explain it by saying that. I also translated my letter into Portuguese in case English might have proven a barrier.

IMO - you have not understand the concept of LC50 96 H the right way.It doesn't say that numbers below this won't kill or hurt fish during 94 hours. - it only says that concentration of this type kill 50% of the tested population during a 94 H expose in their test run. That´s it. Its the scientific accepted test of acute toxicity. In this way this study is in line with many other studies of LC50 in marine fish.

The true deadly or harmful concentration for a species is always depended on individual circumstances.

IMO - you have rejected a scientific study just because you didn't understand the concept. They are NOT saying that lower concentrations don't kill fish or are harmful to fish - they are only saying that at these concentration of NH3-N, 50% of the test population died within 24, 36, 48 and 92 hours in their test run.

Your claim that TAN of 0.8 to 1.5 mg/L its dangerous for fish without mention salinity, temp and pH can be both true and false - it all depends on salinity, temp and mostly by pH. And thank´s god for that - if it was not like that it should be impossible to transport fish in plastic bags for a prolonged time - I have measured pH of lower than 6.7 and TA higher than 5 mg/L in bags transported for 48 H - and no problem with fish - this because the deadly NH3 concentrations during this low pH only is around 0.012 mg/L NH3-N.

However - I agree with you that during normal temp, salinity and pH in a reef aquarium 0.8 mg/L TAN (Total Ammonia Nitrogen) corresponding to around 1 mg/L TA in a normal reef (Total Ammonia) can be deadly for individuals of many reef fish species and probably cause sublethal damage in lower concentrations.

But this was not what we discuss here - your claim was that these people was flawless with their scientific reports and use this report in order to doubt the one I link to.

IMO - this report fulfil the scientific standards and I do not see a reason to doubt either this study or the one I linked to.

Sincerely Lasse