temperature range for Oxydoras Niger

[Viktor Jarikov]

From Fish Base:
Environment
Demersal; freshwater; pH range: 6.0 - 7.8; dH range: ? - 25
Climate / Range
Tropical; 21°C - 24°C (Ref. 2060)
Biology
Occurs over mud in streams and lakes. Forms schools (Ref. 9084). Feeds on detritus, chironomid and ephemeropteran larvae, and crustaceans (Ref. 9096). Known from temperatures ranging from 24-29.8 °C, pH range of 5-9, and an alkalinity range of 42-142.

VJ:

First of all, that's a very narrow temp window of 3 degrees.

Second, do I read it right that the upper limit can be 24-30 oC? Not sure if I am reading it right (because, e.g., the pH range is wider on both sides in the "Biology" section vs. the "Environment" section, which makes sense, but the temp range is strange to me as it does not correspond with the "Climate/Range" section).

Third, not sure if this means that above 24 oC they are uncomfortable or stressed and should be attempted to never be kept at above 24 oC.

[MatsP]

I suspect:
1. That the Cat-eLog (and fishbase, which we got the information from) is wrong.
2. If we can find a "better" answer, we should have a post in the bugs section.

Pier Aquatics keep a group of them in the cold-water section (indoors, but outside the main fishroom, so cooler than your average tropical tank).

--
Mats

[Viktor Jarikov]

Thanks, Mats. Anybody else?

[MatsP]

I actually sent an e-mail to Mark Sabaj. He seems to think that 21-24'C is consistent with the large bodies of water where these fish are found when mature. At smaller size, they would be happy at higher temperatures. However, he also confessed to "not often swimming in the deeper parts of the river" so wasn't quite sure what temperature to expect.

It does, however, make sense that mid-river water is cooler than the shallow, slower moving sections.

--
Mats

[nicofish]

strange I was thinking about temperature and large cats a while ago and came to the conclusion that they should be tolerant of changes seeing how they move from shallow to deep in different currents because they live in big water

then again I dont know much it was just a thought sorry this was not very relevant to the thread.

[Bas Pels]

Generally speaking, I think a big body of water will have a temperature quite close to the average temperature found there

The Amazon river flows almost parallel to the equator, and the climate does not change much - the temperature will be close to 29 C or more

Very deep rivers in Europe tend to be cold, but do remember, the average temperature in our part of Northern Europe - NL, GB is something like 10 C, and our sommers are short. Further, these ivers are typically fed from glaciers -that is ice.

The Amazon river comes from the Andes, therefore it is fed from ice, but is is such a long river, the waterwill take weeks to reach the ocean, and especially from Manous the Amazon river is better described as a very long lake. If I remember correctly, the last 800 km has a drop of 1 cm per km - that is a total of 8 meters. So the Amazon does not flow very fast and has a lot of time to warm up, even the deepest parts.

Now I know cold water does not mingle very well with warm water, and perhaps the deepest parts might manage to refrain from getting warm, but 21- 24 C is, frankly, hard to believe

[nicofish]

this is more of a pimelodus thing. I am not sure if o. niger can be found in these water.



what about where the amazon meets the rio negro the images are stunning I imagine that the large cats that live there must swim through very different waters, so I imagine these fish dont care much for water params as long as you stay with in the range of the amazon and the rio negro. really with suck large rivers I suppose its hard to tell
hmmmmmm I like fish because they give me something to occupy my thoughts with

[Viktor Jarikov]

I actually sent an e-mail to Mark Sabaj. He seems to think that 21-24'C is consistent with the large bodies of water where these fish are found when mature. At smaller size, they would be happy at higher temperatures. However, he also confessed to "not often swimming in the deeper parts of the river" so wasn't quite sure what temperature to expect.

It does, however, make sense that mid-river water is cooler than the shallow, slower moving sections.

From this discussion, please see post #7 by Drstrangelove http://www.monsterfishkeepers.com/forum ... st-7318661 who cites a 1963 study:

"The following rivers and locations were found to have nearly identical water temperatures all day long at depths of surface, zero feet (surface), 10 feet and 50 feet of 82.5-86.0 F. In short the range is very small 24 hours per day at any depth of 50 feet or less within these locations.

Baia de Guajara
Rio Para
Estraito de Boiuca
Furo do Tajapuru
Furo do Ituquara
Amazon River (south channel)
Rio Tapajos
Rio Negro
Parana do Careiro
Rio Solimoes
Rio Madeira"

How to make sense of these numbers given what Mark Sabaj is saying?

[racoll]

Generally speaking, I think a big body of water will have a temperature quite close to the average temperature found there.
The Amazon river flows almost parallel to the equator, and the climate does not change much - the temperature will be close to 29 C or more

The following rivers and locations were found to have nearly identical water temperatures all day long at depths of surface, zero feet (surface), 10 feet and 50 feet of 82.5-86.0 F.

This^.

Without wanting to flog the dead horse of Amazon water temperatures any more than is necessary, I should mention again that temperatures much below 24C simply don't exist here in the lowlands.

Perhaps in the super-deep sections of big rivers it's predominantly cool, but this is irrelevant as O. niger is not a deep water specialist. It's a fish with a wide distribution and is found in main rivers, small tributaries and floodplain lakes etc. It's regularly part of the commercial fish catch.

A general temperature of 25-30C would be more appropriate, but I am sure this fish will tolerate lower temperatures than this in aquaria. It all depends what the temperature values in the CLOG are trying to represent.

[Viktor Jarikov]

Thanks, Rupert. This is what the PCF list of definitions states about the temperature entry: "Temperature The range of warmth a species can tolerate, noted in both degrees Celsius and Fahrenheit."

It sounds like I always read it - a range of tolerance. Hence was my dumbfounded OP question, which still hangs half out in the open. The same question arises in the case of Pterodoras granulosus entry.

I think the temp numbers as currently presented are misleading and should be changed but I still leave plenty of room for my being wrong.

BTW, I didn't know that Amazon water temperatures were a dead horse. Would you explain how ever briefly, please?

[racoll]

This is what the PCF list of definitions states about the temperature entry: "Temperature The range of warmth a species can tolerate

Yeah, I never liked that personally. It's essentially an untestable hypothesis. Who deliberately puts their catfish in conditions that they may not like to find out if they die or not? These tolerance ranges just confuse people and make them think it's okay to put a 20-25C fish together with a 25-30C fish, but where in reality the ideal comfortable temperatures would be 21C and 29C respectively, so not a good mix at all.

I didn't know that Amazon water temperatures were a dead horse. Would you explain how ever briefly, please?

Sorry about that Viktor. Was just a snide reference to recent and particularly unpleasant thread where I got trolled on this subject.

[Viktor Jarikov]

No problem.

Yeah, I never liked that personally. It's essentially an untestable hypothesis. Who deliberately puts their catfish in conditions that they may not like to find out if they die or not? These tolerance ranges just confuse people and make them think it's okay to put a 20-25C fish together with a 25-30C fish, but where in reality the ideal comfortable temperatures would be 21C and 29C respectively, so not a good mix at all.

I see. I always read it differently. I thought it meant "comfortable tolerance", not "when it dies / falls ill from cold and when it dies /falls ill from heat". Because only the former is of importance to a fish keeper, not the latter so much albeit knowing the latter numbers can be of use so we know what to avoid. I've been reading the temp range as "the range of comfortable, for-live keeping, or, in other words, the range of comfortable temps in the wild".

As for the other point, is there in reality such a thing as the ideal comfortable temp, seeing how the temperature is subject to time of day, weather, depth, turbidity, current, season, vegetation, hot and cold spring action, etc.? Or is it pretty stable year round in Brazil (tropical) waters?

[racoll]

I thought it meant "comfortable tolerance", not "when it dies / falls ill from cold and when it dies /falls ill from heat". Because only the former is of importance to a fish keeper, not the latter so much albeit knowing the latter numbers can be of use so we know what to avoid. I've been reading the temp range as "the range of comfortable, for-live keeping, or, in other words, the range of comfortable temps in the wild".

Yes, I am being a little dramatic, but I do think there is a better way to do this that offers more information to the CLOG user.

As for the other point, is there in reality such a thing as the ideal comfortable temp, seeing how the temperature is subject to time of day, weather, depth, turbidity, current, season, vegetation, hot and cold spring action, etc.? Or is it pretty stable year round in Brazil (tropical) waters?

In the lowlands near the equator it's very stable. Temperatures are extremely consistent, and seasonal variation is much smaller than people appreciate.

[bekateen]

I see. I always read it differently. I thought it meant "comfortable tolerance", not "when it dies / falls ill from cold and when it dies /falls ill from heat". Because only the former is of importance to a fish keeper, not the latter so much albeit knowing the latter numbers can be of use so we know what to avoid. I've been reading the temp range as "the range of comfortable, for-live keeping, or, in other words, the range of comfortable temps in the wild".

As for the other point, is there in reality such a thing as the ideal comfortable temp, seeing how the temperature is subject to time of day, weather, depth, turbidity, current, season, vegetation, hot and cold spring action, etc.?

Hi Victor,

Are you familiar with the concept of a "tolerance polygon?" It's a concept developed by physiological ecologists (people who study the physiology of animals in the context of the animals' specific environments) to describe how the survival, living, thriving, growing, and breeding abilities of an animal change as the animal is exposed to, and acclimates to, different environmental parameters (e.g., acclimating to a new temperature, which enables you to then live across a new range of temperatures).

A "typical" tolerance polygon looks like this: (Look at the middle drawing)

This shows several theoretical polygons for an animal.

• The outermost (blue) polygon represents the ranges of temperatures (on the vertical axis) within which an animal can "resist" dying instantly, IF the animal is allowed to acclimate for a while to a less extreme temperature (horizontal axis) near the middle of this range. Above or below the polygon, the animal's death is assured in short order, although the exact time until death may not be known.
• The next inner polygon (red) is the range of temperatures the animal can "tolerate" for a longer period of time, again if allowed to acclimate. But if kept too hot or too cold (above or below the polygon) for too long, the animal will eventually die a premature death.
• The next inner polygon (orange) is the range of temperatures within which the animal will survive and stay healthy for an indefinite period of time, again if given time to acclimate to a nearby, less extreme temperature. However, this range of temperatures is still too extreme for the animal to grow or reproduce very well.
• Finally, the innermost polygon (purple) is the narrowest of vertical temperatures for any given acclimation temperature. Within this narrow polygon the animal is in its "optimal" range of temperatures, and under these ideal conditions the animal will thrive, grow, and reproduce.
• The left and right sides of each of these polygons represent the maximum and minimum acclimation temperature which the animal can achieve and stay inside their polygon. If they are acclimated to a temperature to the left or to the right of the side edge of one polygon, it means they are moving into a less healthy range of temperatures (e.g., from live to tolerate, or from tolerate to resist, etc).

Whenever I see temperature range of an aquarium fish posted in a book or on the internet, what I'm hoping they are telling me is this innermost polygon, the narrow range within which the fish will breed and grow. But if I'm getting this data from a scientific source which is describing where the animal is found, the range is probably one of the wider polygons ("Activity" or "Tolerance," but almost certainly not "Resist") because sometimes in nature the fish may be found under sub-optimal conditions: It can live there, but it may not thrive, breed and grow.

This concept helps explain Racoll's comment:

These tolerance ranges just confuse people and make them think it's okay to put a 20-25C fish together with a 25-30C fish, but where in reality the ideal comfortable temperatures would be 21C and 29C respectively, so not a good mix at all.

Does that make sense?

Cheers, Eric

[Jools]

A couple of points here but first I'd say that I'm entirely open to changing the species data.

First off, the majority of this species offered in the trade are from the upper and not lower half of the Amazon. They are from deeper bodies of water which as has been noted is much more stable temperature away from the shore.

Secondly, the way the site is intend to work (in my head) is that indeed there is a broad tolerance akin to the second most outer polygon in the middle diagram above. Those diagrams are helpful in positioning what we're talking about.

This is for me to do:
The concept is that blog and my cats data will then form average data which is presented on the catelog page. The following data is intended to be presented.

User of the site report keeping this fish at (lowest) to (highest) and an average of (average) temperature.

Breeders report spawning this fish at (lowest) to (highest) and an average of (average) temperature.

I am fully aware this depends on the quality of the data users submit.

As an aside, average time kept and other data similar to that above is also planned.

First I need to implement a process to prune data that has just been left here as people have stopped keeping fish or using the site.

There are one or two things ahead of this in my TODO list which takes about twice as long as in the past with Mats's reduction in programming for the site.

Jools

[Viktor Jarikov]

Many thanks Eric and Jools. These charts bring about needed clarity and a new dimension to my thinking. The idea you have conveyed Jools is grand albeit it sounds labor- and time-intensive.

[racoll]

The concept is that blog and my cats data will then form average data which is presented on the catelog page.

This is a super-cool idea Jools!

[bekateen]

Hi Victor,

Are you familiar with the concept of a "tolerance polygon?" It's a concept developed by physiological ecologists (people who study the physiology of animals in the context of the animals' specific environments) to describe how the survival, living, thriving, growing, and breeding abilities of an animal change as the animal is exposed to, and acclimates to, different environmental parameters (e.g., acclimating to a new temperature, which enables you to then live across a new range of temperatures).

A "typical" tolerance polygon looks like this: (Look at the middle drawing)Homeostasis tolerance polygon.PNG
This shows several theoretical polygons for an animal.

• The outermost (blue) polygon represents the ranges of temperatures (on the vertical axis) within which an animal can "resist" dying instantly, IF the animal is allowed to acclimate for a while to a less extreme temperature (horizontal axis) near the middle of this range. Above or below the polygon, the animal's death is assured in short order, although the exact time until death may not be known.
• The next inner polygon (red) is the range of temperatures the animal can "tolerate" for a longer period of time, again if allowed to acclimate. But if kept too hot or too cold (above or below the polygon) for too long, the animal will eventually die a premature death.
• The next inner polygon (orange) is the range of temperatures within which the animal will survive and stay healthy for an indefinite period of time, again if given time to acclimate to a nearby, less extreme temperature. However, this range of temperatures is still too extreme for the animal to grow or reproduce very well.
• Finally, the innermost polygon (purple) is the narrowest of vertical temperatures for any given acclimation temperature. Within this narrow polygon the animal is in its "optimal" range of temperatures, and under these ideal conditions the animal will thrive, grow, and reproduce.
• The left and right sides of each of these polygons represent the maximum and minimum acclimation temperature which the animal can achieve and stay inside their polygon. If they are acclimated to a temperature to the left or to the right of the side edge of one polygon, it means they are moving into a less healthy range of temperatures (e.g., from live to tolerate, or from tolerate to resist, etc).

Whenever I see temperature range of an aquarium fish posted in a book or on the internet, what I'm hoping they are telling me is this innermost polygon, the narrow range within which the fish will breed and grow. But if I'm getting this data from a scientific source which is describing where the animal is found, the range is probably one of the wider polygons ("Activity" or "Tolerance," but almost certainly not "Resist") because sometimes in nature the fish may be found under sub-optimal conditions: It can live there, but it may not thrive, breed and grow.

This concept helps explain Racoll's comment:

These tolerance ranges just confuse people and make them think it's okay to put a 20-25C fish together with a 25-30C fish, but where in reality the ideal comfortable temperatures would be 21C and 29C respectively, so not a good mix at all.

Does that make sense?

Cheers, Eric

A recent scientific paper comes back some of the ideas discussed in this old thread: Critical thermal maxima data refers to the space between the outermost and second-to-outermost polygons above - a region of critical temperatures allowing survival (does cause not instant death due to heat) but may lead to physiological disability (and then something eats you and you can't defend yourself or get away).

Desforges, J.E., Birnie-Gauvin, K., Jutfelt, F., Gilmour, K.M., Eliason, E.J., Dressler, T.L., McKenzie, D.J. Bates, A.E., Lawrence, M.J., Fangue, N. & S.J. Cooke. (2023). The ecological relevance of critical thermal maxima methodology for fishes. J. Fish Biol., First published: 07 March 2023. https://doi.org/10.1111/jfb.15368
https://onlinelibrary.wiley.com/doi/10.1111/jfb.15368

Abstract
Critical thermal maxima methodology (CTM) has been used to infer acute upper thermal tolerance in fishes since the 1950s, yet its ecological relevance remains debated. In this study, the authors synthesize evidence to identify methodological concerns and common misconceptions that have limited the interpretation of critical thermal maximum (CTmax; value for an individual fish during one trial) in ecological and evolutionary studies of fishes. They identified limitations of, and opportunities for, using CTmax as a metric in experiments, focusing on rates of thermal ramping, acclimation regimes, thermal safety margins, methodological endpoints, links to performance traits and repeatability. Care must be taken when interpreting CTM in ecological contexts, because the protocol was originally designed for ecotoxicological research with standardized methods to facilitate comparisons within study individuals, across species and contexts. CTM can, however, be used in ecological contexts to predict impacts of environmental warming, but only if parameters influencing thermal limits, such as acclimation temperature or rate of thermal ramping, are taken into account. Applications can include mitigating the effects of climate change, informing infrastructure planning or modelling species distribution, adaptation and/or performance in response to climate-related temperature change. The authors’ synthesis points to several key directions for future research that will further aid the application and interpretation of CTM data in ecological contexts.

[Viktor Jarikov]

Thank you Eric the Watchman! We are lucky to have you and your input. You give a dizzying depth to my otherwise shallow skirting of subjects.