False piraiba, Brachyplatystoma capapretum, ~10", in 4500 gal

[Just Toby]

I take it I lost your interest?

I did not know it needed a response, I think you made a good account of yourself in response to my comment. I do not claim to know the answers, was just making a statement of opinion. I know that you know what you are doing and that means you can keep the parameters well under control.

My point is just how busy it looks to me.

 

[thebiggerthebetter]

I did not know it needed a response, I think you made a good account of yourself in response to my comment. I do not claim to know the answers, was just making a statement of opinion. I know that you know what you are doing and that means you can keep the parameters well under control.

My point is just how busy it looks to me.

Thanks, bro.

One of the reasons the tank looks busier than it is is that the tank is square 13'x13' but the depth perception is incorrect when looking at the tank - it seems 1.5x-2x narrower than it is. Hence, fish that seem to be close are in fact much farther from each other.

The point in my reply was that I shared in your concerns as well and while I think the tank system is likely functioning adequately, I would never ever refuse any help. I love learning and need to learn from everyone on here.

On my end, I'd not say I know all that what I'm doing. For instance, yes, the ammonia and nitrite are zero, as they should be, but I admit that I don't understand enough about what Oddball says about brown blood disease aka Methemoglobinemia.

http://www.aces.edu/dept/fisheries/aquaculture/documents/BrownBlood.pdf
http://www2.ca.uky.edu/wkrec/NitritePonds.pdf

Oddball says that even if the tests read zero, one needs sufficient volume of water for instant dilution to prevent the formation of methemoglobin (met + hemoglobin) from hemoglobin + nitrite.

It seems this problem, unless enough table salt is added to largely alleviate it, is unavoidable in (non-flow-through) aquaculture and in JDM-style fish tanks (so called Japanese Domestic Market tanks where there seems to be more fish than water in one's tank).

I don't know how to make sure I don't have this problem in my tanks. I don't think just perpetually having salt in my fish tank water is healthy for my fish in the long run. Hence, I simply rely on 1 cubic inch of fish per gallon of water rule of thumb to calm my conscience in the first approximation.

Hope this makes sense.

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https://www.addl.purdue.edu/newsletters/1998/spring/nitrate.shtml This small write-up states: "Nitrite levels should not exceed 0.10 mg/L in channel catfish or 0.50 mg/L in salmonids. The LC50 for the majority of freshwater fish ranges from 0.60 to 200 mg/L. Saltwater fish have a much higher tolerance for nitrites."

0.1 mg per liter = 0.1 ppm whilst our best home test kits such as liquid API tests have the lowest detectable level at 0.25 ppm.

I must note in other links I cite here it says that trout and other cool water fish are much more sensitive to nitrite, so I don't get this statement about salmonids above citing higher numbers.

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http://www.aun.edu.eg/developmentvet/fish diseases/7_3.htm says: "Nitrite toxicity is affected by many factors including chloride level in the water, PH, fish size, previous exposure, nutritional status and dissolved oxygen level. Nitrite can become toxic to fish at concentrations as low as 0.5 mg/L (= ppm).

Nitrite, NO2, measured in parts per million (ppm), is the second chemical measurement (after ammonia) made to determine the "health" of the biological filter. Nitrite should not be detectable in a pond with a properly functioning biological filter. Thus the ideal and normal measurement of nitrite is zero.

At all times Levels of nitrite should be kept below 0.1 mg/L."

 

[Just Toby]

I totally agree that the time to convert ammonia and nitrite is an issue especially in low volume to fish ratio or ammonia spike level, we could have filters bigger than our tanks but even then the bioload would not prepare it for a sudden spike. Volume will always win I guess with high enough turnover to clear the waste.

 

[timtk]

On my end, I'd not say I know all that what I'm doing. For instance, yes, the ammonia and nitrite are zero, as they should be, but I admit that I don't understand enough about what Oddball says about brown blood disease aka Methemoglobinemia.

http://www.aces.edu/dept/fisheries/aquaculture/documents/BrownBlood.pdf
http://www2.ca.uky.edu/wkrec/NitritePonds.pdf

Oddball says that even if the tests read zero, one needs sufficient volume of water for instant dilution to prevent the formation of methemoglobin (met + hemoglobin) from hemoglobin + nitrite.

It seems this problem, unless enough table salt is added to largely alleviate it, is unavoidable in (non-flow-through) aquaculture and in JDM-style fish tanks (so called Japanese Domestic Market tanks where there seems to be more fish than water in one's tank).

I don't know how to make sure I don't have this problem in my tanks. I don't think just perpetually having salt in my fish tank water is healthy for my fish in the long run. Hence, I simply rely on 1 cubic inch of fish per gallon of water rule of thumb to calm my conscience in the first approximation.

Hope this makes sense.

********************************************

https://www.addl.purdue.edu/newsletters/1998/spring/nitrate.shtml This small write-up states: "Nitrite levels should not exceed 0.10 mg/L in channel catfish or 0.50 mg/L in salmonids. The LC50 for the majority of freshwater fish ranges from 0.60 to 200 mg/L. Saltwater fish have a much higher tolerance for nitrites."

0.1 mg per liter = 0.1 ppm whilst our best home test kits such as liquid API tests have the lowest detectable level at 0.25 ppm.

I must note in other links I cite here it says that trout and other cool water fish are much more sensitive to nitrite, so I don't get this statement about salmonids above citing higher numbers.

In methemoglobinemia the ferrous moiety of hemoglobin is oxidized to 2+ to 3+ beyond equilibrium levels. Methemoglobin is just hemoglobin in the 3+ oxidation state (of the Fe). It can happen to humans as well as any animal with blood systems like ours. Nitrite is an oxidizing agent so it can perturb the equilibrium to excess methemoglobin. Methemoglobin doesn't transport oxygen as well as hemoglobin, so animals become oxygen starved. What's interesting to me is that nitrate is also an oxidizing agents, more so than nitrite. It also perturbs the hemoglobin methemoglin equillibria and causes methemoglobinemia. Apparently, high nitrate in taps water can cause methemoglobinemia in infants (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1247562/). So I wonder why the first source you linked speaks solely of nitrite? This got me thinking about whether or not nitrate and nitrite have any difference in toxicity. If there are both toxic due to the same mechanism, their relative toxicity should only be a matter of their oxidizing strength...

The formation of nitrite in the aquarium is related to the rate of reaction of ammonia to nitrite which is dependent on the nitrate reductase pathway and the amount of bacteria catalyzing this reaction. If you start detecting nitrite in your tank, add more biological media.

Another solution is to simply increase the oxygen level in the tank. I.e., add more air stones, increase flow, lower temperature. Having salt constantly in tanks is a subject of some contention. Although utilizing competitive adsorption is a clever trick.

 

[thebiggerthebetter]

... Methemoglobin is just hemoglobin in the 3+ oxidation state (of the Fe)...

What could be added I think is that when hemoglobin reacts with chemicals such as nitrite or carbon monoxide, these chemical agents bind strongly to the iron center in the electron donor-acceptor fashion and not only because of the difference in oxidation and reduction potentials but also because iron has spare orbitals while nitrite, carbon monoxide, etc. have free electron pairs. Their affinity to each other is super strong and the binding is highly energetically beneficial and is irreversible.

There is much more to this picture, of course. And this is not a science forum Neither do I have the time to look it up.

... What's interesting to me is that nitrate is also an oxidizing agents, more so than nitrite. It also perturbs the hemoglobin methemoglin equillibria and causes methemoglobinemia. Apparently, high nitrate in taps water can cause methemoglobinemia in infants (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1247562/). So I wonder why the first source you linked speaks solely of nitrite? This got me thinking about whether or not nitrate and nitrite have any difference in toxicity. If there are both toxic due to the same mechanism, their relative toxicity should only be a matter of their oxidizing strength...

We do know that nitrate's toxicity is 1000x that of nitrite, so there must be a reason beyond just the oxidation power of nitrite and nitrate.

For an electron-transfer reaction (or oxidation of an electron donor and reduction of electron acceptor) to occur, the distance between the donor and acceptor is beyond crucial. Nitrite has a reason to tightly bind to Heme or iron in that complex. Nitrate has no such reason, having no free electron pairs.

On the energetic side, the rate of chemical reaction, let it be this electron transfer reaction, depends in the first approximation on a pre-exponential factor and the exponential factor, as in the Arrhenius equation:



The pre-exponential factor may be very large and similar for both nitrite and nitrate, if both have similar oxidation potential. But the exponential factor would be vastly different because the activation energy for the nitrite, that has a reason to tightly bind to iron, would be far lower versus the rather indifferent nitrate, that has no benefit to approach the iron closely.

 

[thebiggerthebetter]

What could be added I think is that when hemoglobin reacts with chemicals such as nitrite or carbon monoxide, these chemical agents bind strongly to the iron center in the electron donor-acceptor fashion and not only because of the difference in oxidation and reduction potentials but also because iron has spare orbitals while nitrite, carbon monoxide, etc. have free electron pairs. Their affinity to each other is super strong and the binding is highly energetically beneficial and is irreversible.

There is much more to this picture, of course. And this is not a science forum Neither do I have the time to look it up.



We do know that nitrate's toxicity is 1000x that of nitrite, so there must be a reason beyond just the oxidation power of nitrite and nitrate.

For an electron-transfer reaction (or oxidation of an electron donor and reduction of electron acceptor) to occur, the distance between the donor and acceptor is beyond crucial. Nitrite has a reason to tightly bind to Heme or iron in that complex. Nitrate has no such reason, having no free electron pairs.

On the energetic side, the rate of chemical reaction, let it be this electron transfer reaction, depends in the first approximation on a pre-exponential factor and the exponential factor, as in the Arrhenius equation:

View attachment 1293509

The pre-exponential factor may be very large and similar for both nitrite and nitrate, if both have similar oxidation potential. But the exponential factor would be vastly different because the activation energy for the nitrite, that has a reason to tightly bind to iron, would be far lower versus the rather indifferent nitrate, that has no benefit to approach the iron closely.

Forgot to add that the infamous poison potassium cyanide (of course the cyanide part) acts by the same chemical mechanism as nitrite and carbon monoxide, eliminating hemoglobin's ability to carry oxygen diatomic molecule.

 

[thebiggerthebetter]

Back to the more fun part. Fish!!!

The thread started a year ago. Good time for an updated video:

 

[thebiggerthebetter]

The big capa has been doing well and is 2' now.

The smaller capa that I got the end of Feb 2017, has killed itself a bit out of the blue. It lived quite well and got established in a 240 gal with 5 P. blochii, 7 synodontis, a dourada catfish of smaller size, and a siamese giant carp, perhaps a few other benign fish.

Since our Distichodus lusosso got seriously bent on killing our purple Labeo in their 240 gal, I had nowhere to place the Labeo - itself a nightmare of a fish with larger tank mates. As it doesn't pay much attention to smaller fish, I placed it in that 240 gal tank.

Same day or the next I blew out my lower back and was bed-ridden for a week. In a few days my wife said that the smaller capa perished. I only assume it killed itself by running into things and walls from getting spooked by the mere presence of a larger, overbearing fish in the tank.

The dourada, which is usually equally spooky, has been fine. No one else showed any problems with the Labeo's introduction so far.

You can see its snout is pretty banged up. It grew from 4" in Mar 2017 to 9"-10" in May 2018. It was still spotted but apparently lost all the spots right before perishing.

 

[Deadliestviper7]

The big capa has been doing well and is 2' now.

The smaller capa that I got the end of Feb 2017, has killed itself a bit out of the blue. It lived quite well and got established in a 240 gal with 5 P. blochii, 7 synodontis, a dourada catfish of smaller size, and a siamese giant carp, perhaps a few other benign fish.

Since our Distichodus lusosso got seriously bent on killing our purple Labeo in their 240 gal, I had nowhere to place the Labeo - itself a nightmare of a fish with larger tank mates. As it doesn't pay much attention to smaller fish, I placed it in that 240 gal tank.

Same day or the next I blew out my lower back and was bed-ridden for a week. In a few days my wife said that the smaller capa perished. I only assume it killed itself by running into things and walls from getting spooked by the mere presence of a larger, overbearing fish in the tank.

The dourada, which is usually equally spooky, has been fine. No one else showed any problems with the Labeo's introduction so far.

You can see its snout is pretty banged up. It grew from 4" in Mar 2017 to 9"-10" in May 2018. It was still spotted but apparently lost all the spots right before perishing.

View attachment 1322536 View attachment 1322537 View attachment 1322538 View attachment 1322539

I think your assumption is correct,loss of color can indicate stress.

How's the labeo from hell?

 

[Matteus]

Well that's sad news. Sorry to hear about your back, are you still bed ridden?

So now I wonder does this guy become food for the big tank then?