Lost a fish. Can you take a look please?

[MnFish1]

@vetteguy53081 - Hanna came back .04. I read Taricha wrote below that it appears I’m safe from ammonia:

A total ammonia of 0.4 is not likely to have a significant effect in most tanks. And it's not clear what your ammonia was immediately after you added the rock.

However you have a different situation - if you check out the calculator below - and given your pH of 8.5 - indeed you have a level that can be toxic (a level of free ammonia = 0.06) - note - I don't know your salinity or temperature - but you can enter the values yourself. I can see a situation where your ammonia level Was borderline - and the rock tipped it into a toxic range - which affected this fish - more than the others. Though not 'toxic' under normal conditions, a level (total NH4+NH3) should not be 0.4. You'll note that Taricha says in a stable tank you can see ammonia of 0.1-0.2 (I disagree with this - in MOST tanks the level is 0). Your level - at 0.4 was double the usual. Note - that he is talking about ammonia toxicity at pH 7.8 in the paragraph you sent - your pH was significantly higher - and ammonia become more toxic very very quickly even with small changes in pH (i.e. NH4 is converted to NH3)

However - if your pH wasn't 8.5 (I didn't understand 'under its usual decline), a total ammonia of 0.4 is not likely to be toxic. Hope this helps.

https://www.hamzasreef.com/Contents/Calculators/FreeAmmonia.php

 

[vetteguy53081]

@vetteguy53081 - Hanna came back .04. I read Taricha wrote below that it appears I’m safe from ammonia:

One's test does not signify your tank to be safe but studies done were good. .04 ammonia is not deadly but you want to be .025 or below

 

[WhatCouldGoWrong71]

75 degrees. This is where I saw him breathing hard. I put the rock in around 8pm. See picture. Decline means, on the normal daily ph decrease.




Well, I shut the doser off. I’m going to have to triple check the math. I’m starting to think I caused this, sadly. The rock and the dosing. I never thought adding rock would be a bad thing. I’m taking it out in a few minutes. It’s only temp anyway and I don’t want a bigger issue in 30 days. Man I feel like crap now.

 

[WhatCouldGoWrong71]

One's test does not signify your tank to be safe but studies done were good. .04 ammonia is not deadly but you want to be .025 or below

I was thinking .25, I’ve been wrong for a long long time.

 

[vetteguy53081]

I was thinking .25, I’ve been wrong for a long long time.

Huge difference. . . LOL.

 

[MnFish1]

I was thinking .25, I’ve been wrong for a long long time.

0.25 is correct. It depends on whether you're talking about free ammonia (NH3) - or total ammonia (NH4). (Most tests check total ammonia). 0.25 is basically normal - depending on the test you're using. So you have not been wrong. zero is the best - but 0.25 would not cause issues in a tank - and most tests are difficult to read between 0 and 0.25. Which test were you using?