It's bigger than the Tang thread

[frankpayne32]

I'm not saying that's not a reliable indicator, but an animal that is stressed out enough (say collection, shipping, untenable environment, etc.) may have "blown out" adrenals resulting in lowered cortisol levels. The adrenals can no longer function properly and produce enough cortisol. Just something to factor in.

True, but I doubt the fish that were used in the study were freshly caught wild fish.

 

[frankpayne32]

I agree that it would be best to use a sampling from experienced as opposed to newbie hobbyists to attempt to quantify this issue. I am by no means convinced, however, that this determination needs to be "individually subjective" and cannot be done in a way where the data can be quantified to provide some reasonable level of objectiveness to the standard.

Variables of measureable criteria for consideration could be: (1) fish size; (2) fish swimming habits or activity level or other general or typical behavorial traits observed in the species; (3) fish weight or estimated weight; (4) growth rate of the fish; (5) typical purchase size or weight of the fish; and (6) typical maximum size or weight of the fish achieved in home aquaria -- just to name a few.

The reason I still hold that it will always be subjective is that of your points: 1, 3, 4, 5, and 6 will be all over the place and will vary a great deal depending upon factors like: genetic individuality of fish, collection site, collection method, wild health state of the fish before capture, nutrition in the home aquarium, as well as a myriad of other variables in each and every home aquarium that affects fish health. So while your listed criteria can be measured I don't believe that the results will be valid in a way that will lead to a viable answer.

 

[Stuart60611]

The reason I still hold that it will always be subjective is that of your points: 1, 3, 4, 5, and 6 will be all over the place and will vary a great deal depending upon factors like: genetic individuality of fish, collection site, collection method, wild health state of the fish before capture, nutrition in the home aquarium, as well as a myriad of other variables in each and every home aquarium that affects fish health.

Absolutely true. Just as vodka dosing can be affected by a myriad of variables unique to a given system and thus is also largely subjective and without adequate controls. This can be overcome just in the same way these limitations have been overcome with vodka dosing to produce a reliable, although not absolutely certain, set of parameters. It just takes careful thought out criteria combined with appropriate sampling and chosen group of people who provide the sampling data. Not objective science, but it is also not pure subjectivity.

 

[frankpayne32]

Absolutely true. Just as vodka dosing can be affected by a myriad of variables unique to a given system and thus is also largely subjective and without adequate controls. This can be overcome just in the same way these limitations have been overcome with vodka dosing to produce a reliable, although not absolutely certain, set of parameters. It just takes careful thought out criteria combined with appropriate sampling and chosen group of people who provide the sampling data. Not objective science, but it is also not pure subjectivity.

I can definitely agree with that statement. :beer: I guess my major issue with this issue is that I find it silly that people are telling me that my hepatus tang needs to live in a 240 gallon aquarium. I fully believe that my hepatus tang will live a healthier and less stressful life in my 125 gallon aquarium than it would in the wild. The only major concern I have with keeping nekton in my aquarium is that I am more or less preventing them from breeding, an organism's sole purpose for existance. :thumbdown

 

[Matt_Wandell]

Hi Stuart, I did not bring up those two situations to sound analogous, but I'm glad it helped you explain your position. In the case of ethanol additions, nitrate and phosphate are easily measured. In the case of the carbon-HLLE connection, HLLE is very easily observed as either existing or not existing in individual fish.

What I am getting from Jay's posts, and I agree with, is that some unambiguous measure needs to be made for fish stress levels or "happiness" before any of us can say that fish are happy, unhappy, stressed, not stressed.

I think we've all got the common goal of making sure that the animals under our care are kept in the best conditions possible, but I do find an argument to be on shaky ground as soon as we start telling people what they can't do. Instead, I'd rather show them what's possible and they can (hopefully) emulate that experience.

My opinion is that the arbitrary limits commonly imposed as a minimum tank size for some tangs just happen to coincide with what is easily affordable and fits in a living room. Based on age/weight/tank size data from lots of public aquariums, I'm sure Jay or I could make the argument that everyone keeping Acanthurus or Naso spp. in tanks less than 2,000 gallons are condemning them to a shorter lifespan, stunted size, depriving them of appropriate social groupings that they would normally experience in the wild, etc., and that none of them should be kept by hobbyists. I imagine that wouldn't be a very popular opinion.

 

[Stuart60611]

Hi Stuart, I did not bring up those two situations to sound analogous, but I'm glad it helped you explain your position. In the case of ethanol additions, nitrate and phosphate are easily measured. In the case of the carbon-HLLE connection, HLLE is very easily observed as either existing or not existing in individual fish.

What I am getting from Jay's posts, and I agree with, is that some unambiguous measure needs to be made for fish stress levels or "happiness" before any of us can say that fish are happy, unhappy, stressed, not stressed.

My opinion is that the arbitrary limits commonly imposed as a minimum tank size for some tangs just happen to coincide with what is easily affordable and fits in a living room. Based on age/weight/tank size data from lots of public aquariums, I'm sure Jay or I could make the argument that everyone keeping Acanthurus or Naso spp. in tanks less than 2,000 gallons are condemning them to a shorter lifespan, stunted size, depriving them of appropriate social groupings that they would normally experience in the wild, etc., and that none of them should be kept by hobbyists. I imagine that wouldn't be a very popular opinion.

Hi Matt. I often like to take quotes from other people's messages and use them for my own purposes. I guess the key here is that the limits are not merely selected arbitrarilly but instead upon some measureable rationale. I acknowledge that establishing such rationale does pose some challenges and needs to be done so in a careful and thoughtful way. However, I am not convinced that this is something that cannot be accomplished and result in a means for determining minimum tank size that has merit in the hobby and which is not purely subjective, arbitrary or capricious.

 

[logan 12]

One thing that I would like to add is that fish mortality rates are around 90% from age zero to age one. If the fish is harvested (put in your aquarium) at this young age or even at any young age, the fishes life is going to be prolonged in the aquarium due to high mortality rates with in a population that occur in nature. Even a few years in a tank maybe more of a life then the fish would ever have in the wild. That is why fish lay hundreds/thousand of eggs only a few actually make it to reproductive maturity to benifit the natural population. Do you think that your dog would live its full life in the wild? There is a slight chance, like the chance of you going out and catching that trophy fish that makes the headlines in the news..... Does not happen too often. Even think of the human population, and how we have managed to ensure that most of us live a long life, instead of to the age of 30.

 

[frankpayne32]

Solid point.

 

[Angel*Fish]

True, but I doubt the fish that were used in the study were freshly caught wild fish.

I'm not understanding what you're saying - what do freshly caught wild fish have to do with my point?

 

[Stuart60611]

Frank and Logan:

Definitely a solid point. One of the things we can offer our fish in captivity that is not available in the wild is an environment free of predation. I do not, however, believe that simply because we can eliminate predation in our captive home aquaria environments is tantamount to a license to house fish in too small of a system which otherwise negatively affects the health of the fish. In my view (and reasonable opinions can certainly differ here), once we take a fish out of its natural wild environment and keep it in our glass boxes for our own pleasure we have a responsiblility to do so in a way which best ensures that the manner in which we are artificially keeping the fish does not substantially impair the fishs' health. I am sure someone will post something to the effect of how do we know that too small of a system negatively affects a given fishs' health. Again, what we are left with, like most things in this hobby, is only anecdotal evidense until formal science can be conducted to demonstrate this with scientific certainty. The lack of the availability of unchallengeable science in this regard is not imo an excuse for inaction, especially in the face of a plethora of anecdotal evidence strongly suggesting that too small of a system can have dire negative health effects upon certain species of fish. None of us hobbyists waited for exact science to be conducted on how to properly keep the fish in our tanks before we decided, for our own pleasure, to take the fish out of their natural environment, and therefore, there is no valid or ethical reason to wait for exact science to develop to determine what size tank should be used to artificially house a given fish.

 

[frankpayne32]

I'm not understanding what you're saying - what do freshly caught wild fish have to do with my point?

Perhaps I misunderstood what you were saying. I thought you were saying that stressed out fish (from capture and transport) would have "blown out" adrenals and therefore have suppressed, and therefore misleading, cortisol levels.

 

[frankpayne32]

In my view (and reasonable opinions can certainly differ here), once we take a fish out of its natural wild environment and keep it in our glass boxes for our own pleasure we have a responsiblility to do so in a way which best ensures that the manner in which we are artificially keeping the fish does not substantially impair the fishs' health.

You said it. :thumbsup:

 

[JHemdal]

All,

I heard back from the cortisol researcher, and he had some very interesting information. I'm not saying this is the last word on this subject, but it is pretty definitive, coming from somebody who has actually measured stress levels in fishes:



" The simplest response is that, using fecal cortisol as an indicator of stress, we have found that after adaptation for a week or so and observation that established lack of conflict if another fish was in a given tank, cortisol levels were basal and the same for a 45 gallon vs. 150 gallon tank. This was true for parrotfish and koi over multiple-month periods (and for grouper, chub , puffer and wrasse across at least a month). When I say 'basal' levels, I am referring to levels we determined for >100 parrotfish in the wild over several years in 'protected' reefs in the USVI and Bahamas."

And with that, I bid you all adieu!

Goodbye,


Jay

 

[Stuart60611]

All,

I heard back from the cortisol researcher, and he had some very interesting information. I'm not saying this is the last word on this subject, but it is pretty definitive, coming from somebody who has actually measured stress levels in fishes:

" The simplest response is that, using fecal cortisol as an indicator of stress, we have found that after adaptation for a week or so and observation that established lack of conflict if another fish was in a given tank, cortisol levels were basal and the same for a 45 gallon vs. 150 gallon tank. This was true for parrotfish and koi over multiple-month periods (and for grouper, chub , puffer and wrasse across at least a month). When I say 'basal' levels, I am referring to levels we determined for >100 parrotfish in the wild over several years in 'protected' reefs in the USVI and Bahamas."

And with that, I bid you all adieu!

Goodbye,


Jay

And that proves what? Virtually no one here keeps parotfish because of how large they get and their dietary requirements. None of us keep koi in a marine system. Puffers, groupers, and wrasses consist of groups of fish who tolerate small tank size much better than most (include triggers in that list). How about large angels and tangs? These two groups of fish are known throughout the hobby to be the groups of fish most affected by small tank size, and groups of fish who have been reported to have the most severe adverse health reactions to unduly small tank size. This data convinces me of nothing in terms of undersized tanks not being an important health issue for certain groups of fish. Plus, Jay, your "Tang Police" title of your article and some of your other comments and published statements you cite as purportedly objective scientific facts have been called into question by many on this thread, including a Team RC member with a doctorate in biology and former college biology instructor whom you posted had admitedly superior credentials to yours. As such, I would much prefer to actually see this study you cite from its source rather than rely upon your purported non-bias summary of its findings. I would also state, as you indicated in this thread, that your opinions about minimum tank size in home aquaria not affecting the health of marine fish comes from someone who has not maintained a home aquarium in over 20 years, and therefore, imo any opinion you have about minimum tank size in home aquaria is indeed suspect. Your opinions in this regard also run counter to the published opinions of some notable experts on the topic who have been keeping home aquariums for a longer period of time than you have not-- one of which I provided a link to on the first page of this thread. Institutional aquaria is often not materially similar to home aquaria which you seem not to recognize and to which you have no recent personal experience.

 

[logan 12]

Stuart

I am not just talking about predation, life is hard out in the sea/ocean. Competition is the main source of mortality in a fish population. Both competition amoung diffrent species and each other within that fish species.

One proccess that can be applied to a reef is a managment plan which I believe is what Hawaii has done to sustain a population of yellow tangs or at least what I hope is being done. Like a fishery a population can be sampled and a OSY can be determined to keep a population at its max without hurting the population. This will allow a harvest of so many yellow tangs out of the system. Similar to any fishing that is done there is always a limit set to keep the population stable (OSY) and producing. There will always be a demand for marine fish, but if they are managed correctly I do not really have a problem with them being taken from the wild at an early age.

I am not promoting you go out and buy a tang for a small aquarium. Just informing, which is what this site is set up do to. In my mind there is no real solution to this problem all that we as hobbiest can do is inform other hobbiest and new comers to allow them to make the best decisions for their own personal box of paradice.

 

[Angel*Fish]

Too bad there were no results on tangs or angels or information about the size of the fish.

 

[Stuart60611]

Too bad there were no results on tangs or angels or information about the size of the fish.

This is another very important point. A one inch baby parotfish may not be very stressed in a 45 gallon system, while a 15 inch one may be very stressed. I also think tank dimensions are very important here. As we all know, most fish value length more than any other dimensional measurement. How much longer was the 150 gallon tank than the 45 gallon tank? I could envision a scenario where you could have a 150 gallon tank which is not much longer than the 45 gallon tank which could also explain why there may not have been much differentiation in stress levels between the two systems.

 

[logan 12]

This is another very important point. A one inch baby parotfish may not be very stressed in a 45 gallon system, while a 15 inch one may be very stressed. I also think tank dimensions are very important here. As we all know, most fish value length more than any other dimensional measurement. How much longer was the 150 gallon tank than the 45 gallon tank? I could envision a scenario where you could have a 150 gallon tank which is not much longer than the 45 gallon tank which could also explain why there may not have been much differentiation in stress levels between the two systems.

Point well made, take for example a 33 that I have...... It's 4ft or 48 inched long and provides the same length as a 55,75 or 90 gallon.

 

[Matt_Wandell]

I am sure someone will post something to the effect of how do we know that too small of a system negatively affects a given fishs' health.

I think you are misunderstanding the counter argument. Clearly if a tank is "too small" for a fish, then obviously it will be impacting the fish's health or stressing it somehow. I think we all agree that fish should not be put into tanks that are too small for them. The question that has decidedly arbitrary answers is what exactly is "too small"?

So, would you care to list your numbers for what you feel is the minimum tank size for a given species to live a long healthy life? For the following species please. Obviously it's not an all inclusive list, but provides a broad range of sizes found in the family.

Acanthurus sohal
Acanthurus lineatus
Acanthurus leucosternon
Acanthurus dussumieri
Naso lituratus
Naso vlamingi
Ctenochaetus tominiensis
Ctenochaetus strigosus
Zebrasoma veliferum
Zebrasoma scopas

Thanks,

 

[Stuart60611]

I think you are misunderstanding the counter argument. Clearly if a tank is "too small" for a fish, then obviously it will be impacting the fish's health or stressing it somehow. I think we all agree that fish should not be put into tanks that are too small for them. The question that has decidedly arbitrary answers is what exactly is "too small"?

So, would you care to list your numbers for what you feel is the minimum tank size for a given species to live a long healthy life? For the following species please. Obviously it's not an all inclusive list, but provides a broad range of sizes found in the family.

Acanthurus sohal
Acanthurus lineatus
Acanthurus leucosternon
Acanthurus dussumieri
Naso lituratus
Naso vlamingi
Ctenochaetus tominiensis
Ctenochaetus strigosus
Zebrasoma veliferum
Zebrasoma scopas

Thanks,

Matt:

I think I understand the issue and fully recognize the difficulties of providing not mere whimsical determinations of what is an appropriate minimum tank size for a given species and instead attempt to fashion methodologies which are more grounded in measurable criteria.

I have also never advocated that I should be the source for seting minimum tank size for any given species because I feel definitely unqualified to do so. Rather, I have been vigorously advocating for the notion that making such a determination is indeed possible using some level of measurable criteria and desireable for the health of fish. In this regard, I have atempted to demonstrate why I believe this is so and attempted to provide constructive suggestions on how to best accomplish this undertaking. I think the "experts" in the hobby, like yourself, should ultimately provide data for these determinations and indicate whether the application of these metrics (as well as deciding which metrics to use) in your opinion bears some relation to what you have observed in reality based on your considerable experience in the hobby. I am just the conductor here -- musicians are going to have play the music.