Fish And Temperature Changes

[TwoTankAmin]

A lot has been discussed in the  recent thread on acclimation. A certain amount of this discussion related to temperature and acclimating fish from one temperature in the bag to their ultimate temperature in the tank. Most of that discussion in the Tropical Fish sub-forum is pretty much anecdotal. Since I am the one who is always on the lookout for science to confirm or refute the "common" wisdom, I located this pretty interesting study regarding fish and temperature and their abilities to live and or adapt to different extremes and changes. It is not for the faint hearted as it will take effort to understand it and more work to find the parts directly related to fish being exposed to rapid temperature changes which is just a part of the overall study. One interesting note, it references a lot of studies going back a pretty long time.
 
If anybody wants to plow though it, it would be interesting to hear what you think in this regard. It may help us understand how much change fish can take and how long acclimation for temp might need to be.
 
Temperature tolerances of North American freshwater fishes exposed to dynamic changes in temperature
http/www.fishsciences.net/reports/2000/EnvironBiologyFishes_58_237-275_Temperature.pdf
 
It does date to late 1990s- submission was 1998, acceptance was1999 and publication was in 2000.

 

[snazy]

I don't acclimate for temperature. I acclimate to match other parameters like PH and TDS. And I never acclimate floating a bag. I do drip acclimation.
Other than that, I've forgotten the heater off so many times that it's becoming way too often. A couple of days ago I left my betta tank's temperature reach below 20s because the tank is next to the window and I conveniently had it opened while the heater was off.
And sometimes annecdotal evidence isn't completely annecdotal because it's called first hand experience. The problem is, we reach the wrong conclusions sometimes, which leads to the wrong message.

 

[TwoTankAmin]

snazy, I expect to get reamed out for asking. But since this is the scientific section, and since I linked to a study/reprot on fish and temperature change, what has your anecdotal experience got to do with things.
 
Where are your temperature numbers, where are you time numbers, where are your rate of change numbers etc.
 
Anecdotal evidence in the face of measurable and quantifiable phenomena is not worth much. You let your bettas get cool, so what does this mean or tell us? Low 20s means what? How fast was the change? Where was the temp. before it went down. How did you measure the effect this had on the fish? Now had you recorded all this stuff, even using low tech tank thermometers etc., you would have at least been in the ballpark of science.
 
What exactly does how you, I or anybody else on this forum chooses to acclimate their fish have to do with the science behind the effects that direction, amount and speed of temperature change has on fish?  And I would also ask you how much of the study you read?

 

[snazy]

Below 20s mean 19 and the temperature is usually 27.
It took 24 hrs about for me to notice, so that's what it took for the temperature to drop.
I haven't measured any effect yet because it was a few days ago. What do you need me to measure as in side effect?
I wouldn't be such firm beliver in some "scientific" experiments too. They can get out of hand as well.

 

[Mikey1]

tropical fish are very tolerant to a wide range of temperatures, as long as the temperature change is very gradual and slow

 

[TwoTankAmin]

snazy- Did you read any part of the study? Is this still the scientific section?
 
So your rate of change would be about 8C/day or about 24 hours and the rate of change is about .333C per hour. Is what you are stating is that the safe range for bettas to live in is 19-27C? Are you saying the safe rate of temp change in a downward direction for bettas is .33C/hour? What exactly is your betta "research" telling us? And can anybody replicate your methods and get similar results? That is one of the hallmarks of the scientific method. It is also why anecdotal results are worthless because nobody is able to replicate the conditions and methods because they are not speficied.
 
It is real simple to say "I wouldn't be such firm beliver in some "scientific" experiments too. They can get out of hand as well." HUH?

?
 
That is not very meaningful. I offered you a specific scientific study above. It is perfectly acceptable for you to read it and then to show where the research involved was not conducted properly so the results would not be reliable. You could argue the methods were not proper or not controlled, you could argue the data doesn't support conclusions, you could find other research that contradicts what was in the linked study. Any and all of these are legitimate ways to dispute the science.
 
So are you stating the linked study, which it appears you have not read yet, got out of hand? If I am out of line and you have indeed read the study, or at least a lot of it, which of their results and observations are you disputing and why? Further, should one equate your experience with one tank with a few bettas with a study in which they cosidered that:

We found more than 450 individual temperature tolerances listed in 80 publications which present original dynamic temperature tolerance data for 116 species, 7 subspecies and 7 hybrids from 19 families of North American freshwater fishes. This total represents about 1/3 of the families and 1/6 of the known North American freshwater species. Temperature tolerance data were partitioned by experimental approach, i.e., critical thermal method (CTM) and chronic lethal method (CLM), and direction of temperature change.

 
 
Please, may I ask folks who may be reading here to do this. Here is a link to a very good concise explanation of the scientific method. When I talk about the science, this is what I am talking about. It may help some folks to better understand what is involved. It certainly should explain the sort of things which are appropriate for this particular area of the forum.
Introduction to the Scientific Method
http/teacher.nsrl.rochester.edu/phy_labs/appendixe/appendixe.html
 

Mikey1- not to argue up or down with what you state, but can you please point to anything close to science to support what you stated? Which tropical fish and to which temperatures are your referring and to what rates of change and in what directions?

 

[snazy]

So your rate of change would be about 8C/day or about 24 hours and the rate of change is about .333C per hour. Is what you are stating is that the safe range for bettas to live in is 19-27C? Are you saying the safe rate of temp change in a downward direction for bettas is .33C/hour? What exactly is your betta "research" telling us? And can anybody replicate your methods and get similar results? That is one of the hallmarks of the scientific method. It is also why anecdotal results are worthless because nobody is able to replicate the conditions and methods because they are not speficied.
 
It is real simple to say "I wouldn't be such firm beliver in some "scientific" experiments too. They can get out of hand as well." HUH?

?

 
I didn't make any conclusions as far as I remember. I just stated the facts and if I have to make a conclusion, it's that the betta didn't die, and a few corys he shares his home with too. I don't advise anyone replicating that but to state that you can't replicate a temperature drop of 8 degrees in a home envoroment is a bit unrealistic. Plus I didn't intend doing it. It was an accident.
If you want scientific experiments, I don't think there will be many here that can conduct them as we aren't willing to experiment with our pets.
 
As for scientific experiments getting out of hand, there are so many it's unreal, not only in the fish hobby but medicine, enviroment, whatever you like.  Many of them can be biased, many can be trustful enough, but we can't be sheep believing something is more trustful just because it has the "scientific" tag on it. That's me. I am a sceptic.
 
But my opinion is not intended towards your own examples or to discredit them in anyway. Please don't turn this into a personal attack but if you didn't want anyone on this non-scientific forum to share an opinion on your scientific thread, then what do you want us to do with your information? We don't even keep fish mentioned in that study.

 

[snazy]

Just to elaborate further on my statement about the "scientific" info being irrelevant or no so important sometimes. This has nothing to do with your example but to explain why I gave such comments.
I can give you scientific info that for example discus can be found in nature in fluctuating temperaturs with the maximum recorded 26-27 in certain habitats.  Also, I can give you a scientific study proving that they are also hebrivores in nature, but then almost the entire aquatic community has been feeding discus for many,many years on very high protein meaty food, including stuff like beef heart and keeps them in temperatures above 29C, all with great success?
So what's the conclusion to that?

 

[TwoTankAmin]

Wild fish and tank fish are not the same thing. Most folks can not get the foods that fish eat in the wild. Most folks have no idea what discus eat in the wild.
 
You could ask Heiko Bleher- I beleive his Discus book vol1 has a section on discus diet. Or maybe ask Discus Hans, you can easily email him.
 
I suggest you read on a forum with folks who keep wilds. Or maybe read this study because it sure doesn't indicate that discus are vegetarian. Could you post a link to the study showing discus are herbivores in nature.
 
Neotropical Ichthyology Print version ISSN 1679-6225 Neotrop. ichthyol. vol.6 no.4 Porto Alegre Oct./Dec. 2008 http/dx.doi.org/10.1590/S1679-62252008000400008 
 
Ecology and life history of an Amazon floodplain cichlid: the discus fish Symphysodon (Perciformes: Cichlidae)
 
William G. R. Crampton
Department of Biology, University of Central Florida, P.O. Box 162368. Orlando, FL, 32816, U.S.A
 

The discus fishes of the genus Symphysodon are popular ornamental cichlids that occur in floodplain lakes and flooded forests of the lowland Amazon Basin. These habitats are characterized by extreme seasonal fluctuations in the availability of food, shelter and dissolved oxygen, and also the densities of predators and parasites. Most aspects of discus biology are influenced by these fluctuating conditions. This paper reports an autoecological study of the western Amazonian discus S. haraldi (until recently classified as S. aequifasciatus). This species feeds predominantly on algal periphyton, fine organic detritus, plant matter, and small aquatic invertebrates. At high water it forages alone or in small groups in flooded forests. At low water it forms large aggregations in fallen tree crowns along lake margins.

From http/www.scielo.br/scielo.php?pid=S1679-62252008000400008&script=sci_arttext&tlng=pt
 
Then when done tell me what you think science says wild discus eat and if you can replicate that diet in your tank.  I am pretty sure small aquatic inverts are not made of plant matter???
 
Clearly you missed this statement in the link to the scientific method as well as what I wrote above;
 

If the predictions of a long-standing theory are found to be in disagreement with new experimental results, the theory may be discarded as a description of reality, but it may continue to be applicable within a limited range of measurable parameters. For example, the laws of classical mechanics (Newton's Laws) are valid only when the velocities of interest are much smaller than the speed of light (that is, in algebraic form, when v/c << 1).

 

That is not very meaningful. I offered you a specific scientific study above. It is perfectly acceptable for you to read it and then to show where the research involved was not conducted properly so the results would not be reliable. You could argue the methods were not proper or not controlled, you could argue the data doesn't support conclusions, you could find other research that contradicts what was in the linked study. Any and all of these are legitimate ways to dispute the science.

 
But again I would implore folks to shift their anecdotal stuff out of the Scientific Section. To stop changing the topic.
 
Snazy- if you want to discus or other scientific topics, whether it be discus diet and temps or something, why not start your own thread. My point in starting this one was to look at the science behind how fish seem to deal with temperature changes. I offerred a link to a decent piece of research on this topic and asked for anybody interested to comment. If nobody cares to, fine, this thread will die. All I ask is folks let it die unpolluted with distractions.

 

[snazy]

I'll just keep it short because I don't want to interfere further. I am not saying that discus are vegetarian. I can say that I can find studies that say they are. One of them is actually the guy you are referring to, Heiko Bleher. It is his book that suggests so based on the food content found in wild discus fish. But there are other researches done and tons of experience that prove it isn't necessarily true. I only wanted to show an example of what scientific studies can be. Unless all of them agree, then one doesn't know which one is true.

 

[TwoTankAmin]

From the discus diet study linked above:
 
"Bleher (2006, p. 510-595) reports detailed observational notes on the diet of discus, taken over many years of field visits to the Amazon basin. He undertook stomach content analyses on over 8,500 discus specimens and also made direct observations of feeding in the wild. Although most of his findings are reported qualitatively, Bleher (2006) presents some quantitative data for the volumetric dietary intake of S. haraldi (although numbers of specimens are not given, p. 593). During the high-water period he reports average stomach contents of: 12% algae and microalgae, 44% plant matter (flowers, fruits, seeds, leaves), 6% detritus, 16% aquatic invertebrates, and 22% terrestrial and arboreal arthropods. During the low water period he reports 25% algae and microalgae, 39% detritus, 9% plant matter, 22% aquatic invertebrates, and 5% terrestrial and arboreal arthropods. Data for S. aequifasciatus and S. discus indicate a larger proportion of algae, plant matter and detritus both for during the low and high water periods. The data presented here for S. haraldi from the Amanã region indicate a pattern of lower dietary variability, and a much larger proportion of periphyton/detritus than reported by Bleher (2006). These discrepancies might reflect the small sample sizes reported here; perhaps much larger samples are required to show the true breadth of discus diet. Alternatively these discrepancies might reflect natural variation in diet among populations and species of discus."
 
Inverts and arthropods are not veggies. Two independent studies done a few years apart. They agree on the types of food the fish eat and they agree that seasonality effects the ratios. They don't agree on the exact ratios nor amount of seasonal changes. So maybe we can not conclude what numbers are correct. But I think we can conclude the fish do eat those types of foods and they do change the balance on a seasonal basis. We accept the information that can be replicated and suspend judgement on the information what was not. That is how I use science. Now if i could find a 3rd and a 4th study on the topic, it might make it possible to reach a few more conclusions or become necessary to modify the two I did make. That is how science works for me.
 
We now return you to to our regularly scheduled program: Fish and Temperature Change............

 

[Mamashack]

Perhaps if you weren't so pedantic and dogmatic TTA and allowed other people to have an opinion different to yours, this thread might have some scientific value. Research only ever "suggests" outcomes, it never "proves" anything and mostly shows the need for more research.

 

[snazy]

I didn't say they are vegetarian. I said herbivore.
Otocinclus eat too certain small iverterbrates and anthropods but they are considered herbivore because the majority of their diet is veg.

 

[TwoTankAmin]

I am not saying that discus are vegetarian. I can say that I can find studies that say they are. One of them is actually the guy you are referring to, Heiko Bleher.

I am not saying that discus are vegetarian. I can say that I can find studies that say they are. One of them is actually the guy you are referring to, Heiko Bleher. It is his book that suggests so based on the food content found in wild discus fish

 
Holy cow- you said it twice. The problem is Heiko did not say it??? He stated the % of the different food matter he found inside the discus. Moreover, the term herbivore is defined in two different ways. One is the majority of the diet is vegetable/plant matter and the other is 100% of the diet is vegetable/plant matter. It can be either, so without your stating which you meant, its hard for me to know.
 
 
I would rather be pedantic than ignorant.
 
"A scientific theory or law represents an hypothesis, or a group of related hypotheses, which has been confirmed through repeated experimental tests. Theories in physics are often formulated in terms of a few concepts and equations, which are identified with "laws of nature," suggesting their universal applicability. Accepted scientific theories and laws become part of our understanding of the universe and the basis for exploring less well-understood areas of knowledge. Theories are not easily discarded; new discoveries are first assumed to fit into the existing theoretical framework. It is only when, after repeated experimental tests, the new phenomenon cannot be accommodated that scientists seriously question the theory and attempt to modify it. The validity that we attach to scientific theories as representing realities of the physical world is to be contrasted with the facile invalidation implied by the expression, "It's only a theory." For example, it is unlikely that a person will step off a tall building on the assumption that they will not fall, because "Gravity is only a theory."
 
Changes in scientific thought and theories occur, of course, sometimes revolutionizing our view of the world (Kuhn, 1962). Again, the key force for change is the scientific method, and its emphasis on experiment."
from http/teacher.nsrl.rochester.edu/phy_labs/appendixe/appendixe.html
 
I am very happy to consider science offered by anybody, I usually beg people to come up with different or more recent science that contradicts what I have found. I want to be proven wrong. Go back and read some of the threads where I offered specific research studies. Then read all the posts after that and what you are going to see is that nobody has responded with science let alone some that clearly superseded what I found. I am happy to admit when I am wrong. I beg people to prove me wrong. In a few threads I have acknowledged where I made a mistake and was wrong. Most recently in daize's bacterial starter thread, I misread the numbers and when she pointed it out I said it was a good catch by her. But nobody notices this part. And nobody posts the supplanting research- yet I am pedantic and dogmatic. Oh well.
 
When good science comes along which disproves earlier research, it replaces it. That is how science works. If you want to show the things I offer for consideration as being the current state of scientific fact are no longer valid, just find the replacement science and show us. There is a big difference in stating something is an immutable fact vs that it the prevailing theory. 
 
I will never accept opinion over science.

 

[eaglesaquarium]

In the summary section of your first posted article:

Empirical findings indicate a constant, linear temperature change of 0.3 C/min meets these criteria.

 
So, if my goal is to acclimate my new fish to their new home, my goal should be to raise (or lower) the temp by less than approximately 0.5F/min, and the fish will suffer no ill effects.  So, if my tank is at say: 76F, and the fish are at say 68F when I get them, the time for them to acclimate to the new temp should be roughly 15 minutes or more. 
 
Of course, this data is specific to North American species.  And there are very few North American species in the trade.  I have South American fish in my tank that I am most interested in temperature studies - currently only Corydoras leopardus.
 
 
Temperature tolerance is a question of interest to me, because the 110G tank I have at school will expose my fish to much higher temperatures than most journals would indicate is "ideal".  A friend has a 30G tank and the temp has been observed to be as high as 84F for prolonged periods during the summer.
 
The tank is currently holding steady at 76F, of course, that's with the HVAC running in the building.   In the summer, they turn off the HVAC to certain portions of the building that are unused.  I assume that the amount of time for my tank to rise to 84F would be a fair bit longer, but what would be the best course of action given this temperature fluctuation?  Would a cool water - water change be a good idea, I suppose not to exceed the drop in temp from 84F to 76F in again less than 15 minutes?  Or would it be best to leave the fish at the higher than preferred temp, because a constant high temp would be better than a temperature that fluctuates on 3 day cycle?