Confused about Oscar death?

[duanes]

The water excreted from the gills, is in essance urine.

The MCL for finished water in the U.S. is 10 ppm.
When I worked as a chemist microbiologist in a water purification plant, water never left the plant at more than 2 ppm.

For me 40 ppm is panic mode, but it never gets there in my tanks, because as soon as nitrates hit 5, I do water changes.

 

[The Morning]

Duane what test kit do you use? I struggle identifying that precise of a measurement with API. I always just change when I see it starting to get orange/red.

 

[LBDave]

I did this thread a bit ago and a lot mentioned TDS.
Nitrates Tested Salifert vs. API

 

[squint]

The water excreted from the gills, is in essance urine.

The MCL for finished water in the U.S. is 10 ppm.
When I worked as a chemist microbiologist in a water purification plant, water never left the plant at more than 2 ppm.

For me 40 ppm is panic mode, but it never gets there in my tanks, because as soon as nitrates hit 5, I do water changes.

Water is not excreted from the gills of freshwater fish. It diffuses into freshwater fish via the gills due to the osmotic gradient. That gradient prevents passive diffusion of water out via the gills. The only possibility would be active pumping for which there is no evidence of.

Ammonia diffuses and/or ammonium is transported through the gills. No water "carries" it out. It is not urination.

The MCL for drinking water in the US is 10 mg/L nitrate-nitrogen which is 44.3 mg/L nitrate. The API nitrate kit and nearly all hobby test kits use nitrate units. The levels of fish "urine" that are unacceptable in aquariums for Oscars are acceptable for infants to drink (and is actually too low).

Anything else but nitrate killed that Oscar. Lighting, aliens, etc., are all more plausible.

 

[LBDave]

Water is not excreted from the gills of freshwater fish. It diffuses into freshwater fish via the gills due to the osmotic gradient. That gradient prevents passive diffusion of water out via the gills. The only possibility would be active pumping for which there is no evidence of.

Ammonia diffuses and/or ammonium is transported through the gills. No water "carries" it out. It is not urination.

The MCL for drinking water in the US is 10 mg/L nitrate-nitrogen which is 44.3 mg/L nitrate. The API nitrate kit and nearly all hobby test kits use nitrate units. The levels of fish "urine" that are unacceptable in aquariums for Oscars are acceptable for infants to drink (and is actually too low).

Anything else but nitrate killed that Oscar. Lighting, aliens, etc., are all more plausible.

Can you clarify where you came up with the 44.3?
From the California Waterboards:

"What are the MCLs for nitrate in drinking water?
The MCLs, in 22 CCR §63341, 10 mg/L for nitrate as nitrogen (N); 10 mg/L for nitrate plus nitrite as N; and 1 mg/L for nitrite as N."

https://www.waterboards.ca.gov/drinking_water/certlic/drinkingwater/Nitrate.html

 

[duanes]

I don't believe nitrate alone killed that oscar, I believe it may have been one of a combination of stresss factors, nitrate being only one.
Stress is the main factor in compromising our fish, leading to disease, the scarring from HLLE (common in oscars and other cichlids) etc, etc, so any time any one of those factors can be lessened, the better, and to me one of the most important, and easiest to do, are water changes (along with appropriate tank size and tank mates).
For fish that come from nearly nitrate free natural conditions like cichlids, very important.
I have been testing natural waters for nitrate here in Panama lately, I have yet to find cichlid habitat with measurable nitrate.
When I tested Lake Michigan daily as part of my job, in the states I never encountered raw water in the lake above above 1 ppm.
So does this suggest we should allow our tanks to reach an unnatural 40ppm? should we be trying to keep fish at the highest levels they can take before being acutely dangerous? I doubt it.
If one was knowingly going to accept high levels of nitrate, I would think it would be advisable to keep fish that live in those conditions naturally, like some anabantoids, and bichirs that can thrive in polluted conditions because they can access atmospheric oxygen.

 

[RD.]

IMO nitrate has always only been meant to be used as a benchmark for overall pollution in an aquarium. Typically when nitrate levels rise, so does the level of organic compounds, bacteria, etc, none of which produce a healthy environment for a fish in captivity. Common sense stuff really.

Add to that exposure to elevated levels of nitrite, and free ammonia, via the cycling process that this fish was exposed to, and gee, I wonder why this fish didn't do so well.

 

[squint]

Can you clarify where you came up with the 44.3?

The MCLs, in 22 CCR §63341, 10 mg/L for nitrate as nitrogen (N); 10 mg/L for nitrate plus nitrite as N; and 1 mg/L for nitrite as N."

It says right there.

For fish that come from nearly nitrate free natural conditions like cichlids, very important.
I have been testing natural waters for nitrate here in Panama lately, I have yet to find cichlid habitat with measurable nitrate.
When I tested Lake Michigan daily as part of my job, in the states I never encountered raw water in the lake above above 1 ppm.
So does this suggest we should allow our tanks to reach an unnatural 40ppm?

Have you compared natural ammonia and nitrite levels to aquarium levels? Why don't we keep ammonia and nitrite at ppb levels in aquariums?

We should also keep fish at natural stocking levels which may be thousands or millions of gallons of water per fish.

 

[LBDave]

I found it. Rounded to 45.
https://www.waterboards.ca.gov/water_issues/programs/gama/docs/coc_nitrate.pdf

 

[Ulu]

. . . We should also keep fish at natural stocking levels . . .

Does anybody do this?

I'd better leave them in the wild. I'm not keeping 1000g to study one Oscar.