# small consideration for reaschers



## pop

Over the holidays I noticed those pretty plastic cup fish I think they are called Bettas. They did not look particularly unhappy and I started to think about how long should they live in an appropriate environment. It seems that everything has a life span now days. I have three pearl groumi and they have lived so far about three years and I wonder where these fish (pearl’s) are in their life’s cycle? Since the Betta fish is in the same family as the pearl’s will the expected life span of the Betta equal that of a pearl’s. 

Will the size of the critter have an impact on the expected life span such as do smaller fish live longer than large fish with all things being equal (healthy environment)? Dose the size of the aquarium have an impact on the life span of a specific fish, take a fifty gallon tank with only one betta fish live longer than a five gallon tank with only one betta, can the stress generated by the fact that there are no other critters in the tank have an effect on life span of the Betta.

Will physical adaptation as the ability to use atmosphere air for respiration significantly increase the life - span over the length of life for critters that can not use the atmosphere for respiration. What is the difference between life-span length when considering evolutionary selection of the way reproduction is accomplished. Water critters appears to have two basic forms of restating the life process through either live birth or by laying eggs to be fertilized. Will fish that reproduce by live birth have an expanded life expectancy greater than water critters that use egg laying method. 

Their are many ways to consider life expectancy and we all want to provide the best experiences we can for our water critters.
pop


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## jaysee

Happy new year pop


Do smaller fish live longer than larger fish? Like how small dogs live longer than big dogs I assume.

Generally speaking, larger animals have longer life expectancies than smaller ones. As an example - the larger the animal the fewer predators it has. There is only one animal that can even think about taking on an elephant, and even then it would have to be old and sick. Plain and simple, the smaller you are the more things there are than can eat you. Too, small animals tend to have faster life cycles, which generally doesn't bode well for life expectancy. They have to live fast to keep their numbers up because so many things can eat them. They also have much larger spawns because of this. They become sexually mature much faster. Large fish can take years to sexually mature while small ones only months. If those fish that take a long time to mature and produce only a few offspring didn't live longer, then they wouldn't continue to exist.

I think it's even true of trees - the larger the species the longer they live.

With regards to fish, there's a lot more than size that influences life expectancy. Geographical location plays a significant role for fish of the same species. Large mouth bass are a great example, as they are found everywhere. Fish A lives up here in the northeast, and fish B lives down in florida. Now they will both attain close to the same adult size (though there are more lunkers down south), but fish A is going to be significantly older than fish B. The warmer water in Florida speeds up the life cycle, which is fueled by the longer availability of food.


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## DKRST

Since what you are asking is really a biology question, I thought I'd take a shot at it!
It all comes down to evolution and natural selection pressures, in terms of the "basic" longevity determined by the genetics of any fish species. The genetics can then be influenced to a greater or lesser extent by selective breeding over time (think coloration, long vs short fins, etc.). 

In general, smaller fish tend to have shorter lifespans. Larger fish will certainly experience shorter lifespans in stressful conditions (like a too-small aquarium), but any size fish placed under stress will experience a shorter lifespan than is natural for it. Stress causes physiological changes that can depress the fish's immune system and make them more prone to disease. "Natural lifespan" is somewhat of an interpretation. Animals in the wild are more prone to predation and typically have shorter lifespans than well-cared for captive animals (but this depends greatly on the specific animal, some do very poorly in captivity).

Now, having said all that, temperature and even food intake can have an impact on longevity of fishes. Not an absolute truth for 100% of all cases, but cold water fish tend to live longer (slower physiology) than warmer water fish. Restricting calories has been shown to increase longevity (but don't starve or freeze your fish!).

Specific adaptations, such as those of the labyrinth fish, don't necessarily add any to the species longevity, but allow the species in nature, to exist in very low-oxygen environments.

Not certain I addressed all your points, but hope I made a start!


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## DKRST

ok, so I missed a couple of pop's points in my first response...



pop said:


> Since the Betta fish is in the same family as the pearl’s will the expected life span of the Betta equal that of a pearl’s.


No, different species even in the same family can have very different lifespans.



pop said:


> What is the difference between life-span length when considering evolutionary selection of the way reproduction is accomplished. Water critters appears to have two basic forms of restating the life process through either live birth or by laying eggs to be fertilized. Will fish that reproduce by live birth have an expanded life expectancy greater than water critters that use egg laying method.


That's probably too big to tackle in it's entirety, unless you want an entire course on the cost/benefits of reproductive strategies, parental care and energy investment, along with evolutionary stable strategies! But, short form: Bony fish ONLY reproduce by eggs. Some seem to have live young not coming from eggs, but what happens is the eggs of livebearers "hatch" internally in the fish we call "livebearers". So, it's a case of internal vs. external fertilization, not really an egg/no egg issue.


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## henningc

Smaller fish live much shorter lives. Most livebearers only 12-18 months. Pearls will live 2-4 years, bettas 24-36 months. I suspect the life in a cup fish will be lucky living a year.


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## pop

Hello DKRST;
I am not asking a question but only considering potential possibilities. I have a different understanding about how evolution may operate. I think you are expressing Lamarckism. I agree with the Lamarck view that behavior selects genetic expression but I don’t think Lamarck view that natural selection operates towards specific goals is correct. In my view natural selection operates similar to the throw of the dice concept where nature works with what turns up and not towards a specific goal creating the abundance of diversity we experience. 


I have to call in question this proposal “ It all comes down to evolution and natural selection pressures, in terms of the "basic" longevity determined by the genetics of any fish species. The genetics can then be influenced to a greater or lesser extent by selective breeding over time (think coloration, long vs short fins, etc.)”, what about mama rats licking their babies research that shows behavior selects genetic expression. My friend do you really believe “longevity is determined by genetics” I have never heard of an longevity gene have you?

You and jaysee both have expressed the view that smaller fish have a shorter life span than larger fish is this just an assumption or are you all basing this on viable experience or better yet verifiable scientific facts.? Jaysee made a post in above thread about small dogs living longer than large dogs and if this is true then the longevity assumption maybe false.

pop


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## Flear

fish lives, ... lives of things in general, ... size is generally a consideration (generally)
crows and parrots can live 100+ years, so there are exceptions, ... but these are exceptions.

dogs make it about 15 years or so for an old dog - only slightly smaller than a human (go by weight) ... but also this comparison is more the exception.

many ways to survive in the animal kingdom, ... make yourself undesirable to eat, or reproduce like crazy because your going to be eaten anyway. an exception being diseases, that some are suggesting may be the true "top of the food-chain", ... but diseases are also small, going back to size being the most significant give away.

i'd agree with GENERALLY go by size.
and how far down the rabbit hole you wish to go will show you more
-how do they reproduce ?
-where are they on the food-chain ?
-where do they come from ? (a life that is calm & relaxed ? or a life where survival is in doubt ?)

the more survival is ensured, the less the genetics have to prepare for the next generation to ensure the species lives on. if survival is always in jeopardy then the genetics will have little room to compensate for a need to consider 20 years, something has eaten you by then, ... genetics only has to keep you alive for 2 or 3 years (and that becomes old)

larger species live longer because of this, there are fewer and fewer predators that can eat them. and, it takes longer to grow larger, and genetics has to allow for this, providing genetic code & information to stay healthy while the animal continues to grow larger, to continue to grow through puberty, to continue to grow into an adult (maturity aside), to continue to stay alive to look after children, to continue to stay alive long enough to provide enough of a child/adult relation as is necessary to ensure the children know how to survive on their own.

the simplest rule of thumb is size, after that, ... that's a deep rabbit hole, how far do you want to go down ?

if you wish to use selective breeding ... more often then not you'll result in a shorter lifespan as selective breeding uses a lot of in-breeding. rumors and myths aside, genetic deformities are (for arguments sake) say 1-in-50,000. if siblings don't have any genetic issues then inbreeding is fine and results can be achieved. we don't see any genetic issues till the genetic code that is responsible for compensating for these issues is no longer present. ... (a subtractive value - i'm no genetic expert). so genetic issues may take many generations to become apparent. statistically, it's 5%, ... a 1 in 50,000 chance of a genetic issue arising in breeding random strangers becomes an extra 5% in breeding siblings. if you notice the neon tetras on the market. due to breeding methods there are a lot that are coming out with kinked spines, ... that extra 5% over years of breeding has multiplied. ... this does not increase their life, but is detrimental to it.


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## jaysee

Small dogs can live up to twice as long as big dogs do. You don't see 20 year old mastiffs.... Whether that means anything or not I don't know.


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## rickey

look at this from a different point view.
Temperature and dietary efficiency play a large role in a fish's life span
Fish riased in cooler water live long that fish kept in warmer water
The more efficiency a food can be converted to body mass the longer the fish lives

 Nutrient requirements of trout salmon and catfish

R


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## jaysee

I think this all becomes much clearer when you step outside the bounds of aquarium fish.


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## Agent13

pop said:


> I have to call in question this proposal “ It all comes down to evolution and natural selection pressures, in terms of the "basic" longevity determined by the genetics of any fish species. The genetics can then be influenced to a greater or lesser extent by selective breeding over time (think coloration, long vs short fins, etc.)”, what about mama rats licking their babies research that shows behavior selects genetic expression. My friend do you really believe “longevity is determined by genetics” I have never heard of an longevity gene have you?
> 
> pop


I seriously tried to avoid this thread.. But.. I can't resist here!
Longevity is largely determined by genetic if you assume all else is the same. For example two fish( two dogs, two humans etc) being kept in identical environment, same food care and absolutely everything else. Only difference is the parents of these otherwise identical creatures. One set being related to eachother or other genetic issues or dissorders the other set not related at all and superior genes. Clearly we shoukd all know which will produce the healthiest fish.. Or whatever creature in question. It's not a"longevity gene" as you call it.. Its general genetic superiority. Resistence to disease, less likely to develop a genetic dissorder and so on. How am I sure about this ? Many long discussions with the genetics specialist at UNC hospitals Chapel Hill NC and my grandfather .. A genetics specialiat as well. 

Ok .. Agent out! :lol:


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## DKRST

pop said:


> Hello DKRST;
> I am not asking a question but only considering potential possibilities. I have a different understanding about how evolution may operate. I think you are expressing Lamarckism. I agree with the Lamarck view that behavior selects genetic expression but I don’t think Lamarck view that natural selection operates towards specific goals is correct. In my view natural selection operates similar to the throw of the dice concept where nature works with what turns up and not towards a specific goal creating the abundance of diversity we experience.
> 
> I have to call in question this proposal “ It all comes down to evolution and natural selection pressures, in terms of the "basic" longevity determined by the genetics of any fish species. The genetics can then be influenced to a greater or lesser extent by selective breeding over time (think coloration, long vs short fins, etc.)”, what about mama rats licking their babies research that shows behavior selects genetic expression. My friend do you really believe “longevity is determined by genetics” I have never heard of an longevity gene have you?
> 
> You and jaysee both have expressed the view that smaller fish have a shorter life span than larger fish is this just an assumption or are you all basing this on viable experience or better yet verifiable scientific facts.? Jaysee made a post in above thread about small dogs living longer than large dogs and if this is true then the longevity assumption maybe false.
> pop


Umm POP, with respect, I think you are somewhat off the biology wagon here. My Ph.D is in Wildlife & Fisheries Sciences and I am most certainly NOT espousing Lamarkian views> Lamark's ideas are totally invalid scientifically. Do genes impact longevity - absofreakinglutely! You are assuming that a single gene controls a characteristic such as longevity. That's not a valid assumption. The more we understand about genetics, the more scientists are coming to realize how multiple genes interact with each other and are influenced, in some but not all cases, by environmental factors.

FYI, behavior does not select genetic expression, it's the other way around, sorry! Genetics are expressed via a behavioral repertoire the animal may select from. And no, that does not rule out learned behaviors, but _learned_ behaviors are not passed down via genes.

Best way to have a long life as a human or as a fish? Have relatives that are long-lived. Genetics yes, but certainly not a single gene. Having said that, even if I have long-lived relatives, I could still get hit by a bus tomorrow (or decide to jump out of my aquarium and carpet-surf!)  

Small dogs do live longer than larger, it's a physiology thing. Dogs are also all the exact same species, just selectively bred. Fish physiology is much different than mammalian physiology.

Small fish have shorter lifespans. Not fiction, not view/opinion, empirical fact. Could there be any fish longevity vs. size exceptions out there somewhere in nature? There probably are, but it would be an exception, not the rule.

Pop, I think you'd really enjoy an evolutionary biology course, or a comparative physiology course. It's neat to see the many ways life works to evolve solutions to problems. Unfortunately, natural selection doesn't necessarily select for longer lifespans, just successful reproduction (that's one reason evolution hasn't "selected against" late-onset cancers). As I said in my earlier response, you asked an excellent, deceptively simple, question that has, to be completely, comprehensively, and accurately addressed, a fairly complicated answer in the biological sciences and I can't get into all the biology background here.

What am I if I'm not Lamarkian? A confirmed neo-darwinist! Darwin didn't know about genetics, so he didn't get it all absolutely perfect! Evolution/nature is certainly not a throw of the dice, nature favors the "house odds" and selects for those genes that enhance survival of a species. 

Fun discussion! Thanks for the original posting. Wish I could type faster though....


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## Tolak

I wonder how the various cory & plec species fit into that. Many of them live considerably longer than comparable sized livebearers & such. If that's an exception it would be a pretty wide swath, not confined to one species of cory or plec. Awesome topic BTW, the genetics of fish are not explored anywhere near as much as other species.


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## DKRST

Tolak said:


> I wonder how the various cory & plec species fit into that. Many of them live considerably longer than comparable sized livebearers & such. If that's an exception it would be a pretty wide swath, not confined to one species of cory or plec. Awesome topic BTW, the genetics of fish are not explored anywhere near as much as other species.


Excellent points and good examples. I don't think I'd categorize corys or plecos as "exceptions" necessarily. Granted, a BN pleco can live 12-14 years, but the larger plecos can live even longer. As I originally stated, no blanket statement is going to be 100% true, there always seem to be living exceptions. As they said in Jurassic Park "life finds a way".

I think in terms of size vs. longevity, we'd have to compare similar fish (catfish to catfish, livebearer to livebearer) to see if the trend holds true (and from a very quick review of reference info, it seems to hold up).

Agree, not much "pet" fish genetics research, more commercial fisheries and medical/environmental genetics research (glofish).


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## pop

Hello DKRST:

WOW!! I have fallen off many wagons in my life but iam not sure I am off the biology wagon as you say, my friend. You are a doctor of wildlife and fisheries science what can I say except that i am one of those high, high school {GED}graduates and here i am conversing with you about all of these mighty ideas. I am honored that you have taken the time to address potential errors of my reasoning. After reading over your post here it appears that we have reach consensuses and agreement that both of us reject the others point of view, therefore it is a waste of time to keep going over old ground. (i could not help but notice that your argument reminds me of the points made in the book the selfish gene and also appears to follow the logic of social biology which was popular 30 or 40 years ago. Are Neo-Darwinist in the closet social biologists? I will follow your advice and learn up on evolution.)

I do have one small question about this statement “the more scientists are coming to realize how multiple genes interact with each other” are you speaking about the type of relationship that exist between genes that result in the physical existence of the chin in humans which there is not a gene for the chin in our genome. Is this a synergistic construct??

You know my friend i am a show me kinda guy and there is a statement about empirical evidence that large fish live longer than smaller fish Please show me this evidence and include the methodology used to reach the conclusions. 

Looking forward to more conversations.
pop


interesting note: President Taylor who died in 1850 has two living GRANDSONS as of January 1, 2014


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## Agent13

pop said:


> interesting note: President Taylor who died in 1850 has two living GRANDSONS as of January 1, 2014


I fail to see how this is interesting. It only mskes news because he was a president. He died an unatural death at 65 and these grandsons were born in the late 20s. Why is this even news.. Lol my living gradmother was born 1918 or 1917. I forget. She is active and healthy and is still a dancer. My family very often lives to abot 100-103. She has tons of great grandchilren 1 even in the womb(my cousins new baby) . My children are her great grandchilren and are only 8 and 5ys old. This just seems quite normal to me.


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## DKRST

Agent13 said:


> My family very often lives to about 100-103.


Dang, I want some of those genes...:lol:


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## DKRST

pop said:


> I do have one small question about this statement “the more scientists are coming to realize how multiple genes interact with each other” are you speaking about the type of relationship that exist between genes that result in the physical existence of the chin in humans which there is not a gene for the chin in our genome.


If I'm understanding you correctly, I think the answer to your question is "yes". I'm talking about the physical expression of genotype, the phenotypic/physical result of the interaction of multiple genes (polymorphism). Think of "blended" features of offspring.


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## jennesque

I think small dogs living longer than large dogs is a poor example of this... Dogs are all very closely related genetically and come from the same DNA and same species. They can all interbreed, not all fish can.

If you look at, for instance, giant neon tetras, I can almost guarantee they die faster than a normal neon tetra.. Their metabolism is going to be different than a normal sized neon, it'll be faster.. Something that grows faster is going to age faster because as the body creates more and more cells, the genetic code ages and gets 'broken' causing problems in the new cells that are created. This is going to be relative to the specific animal though. 

Large dogs age much faster than small dogs.. Dogs may not be genetically designed to handle gigantism as well. But this is also still relative to the specific dog breed.. I have two Australian Shepherds which are medium sized dogs. A lot if people like to breed 'mini' Aussies and they'll do this by constantly breeding the runt of the litter. The runt of the litter is usually genetically disadvantaged in some way shape or form, that's why it's smaller.. And so some people have bred Aussies that weight like 10-15 lbs and are a total genetics mess. These dogs will not live as long as a well bred Aussie and are frequently riddled with health problems.


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## jaysee

DKRST said:


> Dang, I want some of those genes...:lol:


I bet, but they're spoken for ;-)


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## Hallyx

To answer pop's original question that led to this marvelous thread (an answer that seems almost off-topic at this juncture), Most Betta keepers I know are disappointed if their fish lives less than three years and are delighted if they live longer than four. 

They like to brag if their Betta live five or six years with proper care --- good-sized tank, warm, clean water and high-quality, high-protein food. But they are flummoxed hearing of Betta that live that long in small unheated bowls, with infrequent water changes and low-quality food.

Long-time keepers remark at how immunologically fragile the modern pet-store Betta is, insisting that they lived much longer 20-years ago.

It is well-known that colder water can lengthen a Betta's lifespan, but that risks lowering immunity. There is an incipient discussion on the morality of keeping a fish in conditions that lower its metabolism in order to increase its lifespan versus encouraging an active but shorter life.


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## DKRST

Having kept bettas (more than 20 years ago!), I don't remember them living any longer than the current fish, but my memory isn't what it use to be  . I would agree the captive (mass-production) breeding has decreased fitness of some of our fish due to lax breeding and care practices.


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## rickey

*Biodiversity studies in betta fish*

The Siamese ﬁghting ﬁsh: Well-known generally but little-known scientiﬁcally

Cytogenetic study in Betta fish

Biodiversity studies in betta fish just to confuse this even more
Rick


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## pop

Hello DKRST:
thank you for the answer about polymorphism. I have one more question an I suspect you know the answer if you are willing, Do female fish generally have a limited number of eggs or do they produce eggs as needed. also is the amount of eggs the same for live-bearers females and egg laying females?

I must say that I didn’t mean to step on your toes in previous post.
pop

Hello Hallyx:
Thank you for the information about betta’s it’s exactly what I was curious about. what expectation should I have if I was to take one of the cup fish home.
pop

Hello Agent13:

It’s always pleasant experience to read your post. I am impressed by longevity of your family. How nice it is to find out you are connected to Chapel Hill. I have many fond memories of living in CH.

pop


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## DKRST

pop said:


> Hello DKRST:
> thank you for the answer about polymorphism. I have one more question an I suspect you know the answer if you are willing, Do female fish generally have a limited number of eggs or do they produce eggs as needed. also is the amount of eggs the same for live-bearers females and egg laying females?


For egg-layers, do you mean limited in a single breeding season/event or over a lifetime?
Although it sounds really strange, females are born with all the eggs (more accurate to say _potential_ ova) they will ever have, including human females. Never fear, the ovaries won't run out of eggs, there is an excess of available. In human ovaries, it's literally in the hundreds of thousands. I'm assuming it's the same for fish.



pop said:


> also is the amount of eggs the same for live-bearers females and egg laying females?


No idea on that ... sorry! It might depend on the species' reproductive strategy (dump all eggs in a single breeding event, then die (think Salmon) or spread breeding across a lifetime, I just don't know enough to even guess on this one.)



pop said:


> I must say that I didn’t mean to step on your toes in previous post.
> pop


pop, I didn't feel that my toes were stepped on at all, no offense was given and none was taken! Likewise, I hope I gave no offense to you, if I did it was certainly unintended!
After all, the whole point of a forum is _discussion _:lol:


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## Hallyx

Pop, with your background and experience you could easily keep a Betta healthy and active for over three years, assuming you chose a healthy robust individual. 

Buying from a breeder, who is member of this forum, I think would increase your odds of getting a healthy fish. Of course, at the petstore, you can _see_ what choices are available.


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## Agent13

pop said:


> Hello Hallyx:
> Thank you for the information about betta’s it’s exactly what I was curious about. what expectation should I have if I was to take one of the cup fish home.
> pop
> 
> Hello Agent13:
> 
> It’s always pleasant experience to read your post. I am impressed by longevity of your family. How nice it is to find out you are connected to Chapel Hill. I have many fond memories of living in CH.
> 
> pop


If your question is really just that simple. I've always had bettas from a cup at chain pet stores. Have kept plenty over the years still have a few right now. I've always chosen ones that look healthy as far as the eye can tell and in what appears to be good store conditions. Proper food, tank and care... Mine have rarely lived less then 3yrs. Most often 4-5. But i dont like putting expectations on animals i dont know the genetics of. I know the genetics exactly of my dragons.. Well the bearded dragons.. So those I will put expectations on... Not my fish though.


Yes, Chapel Hill is a great place. I love it here. Grew up here too and can say I had the most perfect childhood one could ask for. Beautiful area and great people  While I've wondered around the country a lot (and out), Ive always kept some roots here. Even when i move away I'll come back often.


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