Sorry I didn't get back to you sooner to answer your questions, it has been very busy here.
The differences vary from fish to fish and species to species, but there are a few things I have noticed over the yrs that have shown me a definite pattern between captive bred and wild caught fish. Many wild caught fish show signs of internal parasites that are not common in the captive bred fish, and the wild caught tend to live with these parasites long term whereas the captive bred fish tend to fall victim soon after being infected. There is a definite difference in the immune systems and vulnerabilities between the 2. Another thing I have noticed is that organs such as heart, kidneys, and swim bladder appear to be stronger and contain less fatty deposits than captive bred fishes, along with fewer signs of genetic defect in these specific organs. This shows even in juvenile fishes.
As for the differences having to do with weaker fishes not being killed by predators, no, I don't believe that to be entirely true. While there would be some weight to that theory overall, the things that I've observed don't support that in the majority of cases. My necropsy studies are not and have never been restricted to only fish that have died from disease and/or illness. There have been enough that were deceased due to a physical injury such as ramming too hard into the side of a tank (out of fear/stress) and fighting amongst themselves to protect territory, jumping from a tank to the floor, etc.
I have seen good and bad genetics in both wild and captive bred fishes. I tend to see more evidence of malnutrition in captive bred fish, whether their genetics appear to be good or not. I would call this a problem of the aquarium hobby and trade, not a "weak fish saved from predation". Even with poor genetics from wild species, the evidence of malnutrition is minimal at best. While this isn't the only reason I say this, it is the primary one.
In regards to the runts, no, I don't find that as much as you might think. I have found many cases of simple dwarfism in a wide range of species, everything is proportioned normally, just smaller than the standard/average. I don't have the equipment (or the money for it) to do all of the testing I desire to do, so I can't offer a complete overall of the genetic makeup of the fishes I have studied. I can only offer what I have been able to record with the limited lab and equipment I have had over the yrs. What I can tell you is that being a "runt" is not always a bad thing, but then its not always a good thing either. By just looking at the fish, seldom is there any way to tell unless there is an obvious problem, such as organ malfunction/shut down or physical deformity.
Water chemistry mixed with genetic traits can also contribute to being a runt. I have seen signs of stunting of growth (yes, this often shows up in the organs being under developed, damaged, and/or otherwise affected) in the early stages of development mixed with a weaker genetics as causing smaller fish, while others from the same spawn simply had a stronger immune system overall that the cause of the stunting (typically water chemistry issues) doesn't affect them as severely.
As for the best of colors or fins with runt bettas, if the cause of their being a runt is simply dwarfism, then yes, that is possible, but I can't say that would apply to all or even the majority of cases simply because they are runts or slower growing. It would depend on why they are runts, and while they are alive there is no way to tell, sometimes necropsy study can't tell that either, at least not with my limited equipment.
Try thinking of the fish as children for a moment. Think of one set of parents having 10 children and the differences you would expect to see in those 10 kids. Then put those 10 kids next to 10 other kids from 10 other families, and think about the similarities and the differences. The same thing applies to fish of any species, animals of any species. I often question when people talk about the differences between normal and abnormal, unless its in a situation of disease or illness. What exactly is "normal" and who defines it? Take a tall man with a short woman, and look at the heights of their offspring. The possibilities that fall within a "normal" range are endless. The same thing applies to fish.
While we do know enough about genetics in this day and age to help offer the best chances for specific genetic traits, anything is still a possibility. Some people call that being a freak... but if you do the research and studying, you find that while some things may be rare, there is really nothing freakish about it.
The same can be said of albino traits in fish. In the wild these fish tend to have a very low survival rate and shorter lifespan because the lack of pigment makes these animals stand apart from others of their species, kind of like putting a bulls eye on them and yelling here I am, come get me. Prime target for predation... yet some still survive and even thrive in the wild. In captivity, albinos tend to have longer life spans because they are not targets for predation, however, albinism can often bring with it other genetic defects that have nothing to do with wild vs captive bred. Again, the same perspective can be used to address when referring to runts.
Where the electric blue jack dempseys are concerned, again you are talking about genetics... not all have genetic problems. I would have to assume that both parents of these electric blues are not electric blues? What little I know thus far of that strain of fish, the electric blue coloration is a recessive gene, similar to that of albinism. It can be carried through a series of generations and not show up, and then from 2 normal/standard colored fish you suddenly see it in a small number of their offspring.
I have run into the same traits in my successful angelfish pair where the offspring all show signs of salmon pink fins. Some of the fry have dark, bright salmon coloration in the dorsal fins, others it is not as prominent and as they mature it fades/changes to a light pink tint only. Then there are the few where it gets darker as they mature. This is the result of a recessive gene found in wild altum species. Neither of my parent fish are wild altum, but it is obvious they have it in their heritage somewhere. While my parent fish look a lot alike in markings/coloration, to see the variations in pattern/markings and coloration in their fry was amazing. Some fry appeared as mini me's of the parents, while others were solid white/gold, some were leopard print patterned, some were striped and looked like wild altum... even fins differed greatly within 1 spawn. Short fin, long fin, and somewhere in between... all from the same parent fish,
same spawn.
Genetics can be a complicated science to follow, and the information we have about it changes on almost a daily basis. Things that were believed true 10 - 20 yrs ago have already been proven false. The reasons we believed some things to be true have changed, and continue to change as science continues to push forward. I don't believe we will ever have all of the answers we seek and we should be more appreciative of the ones we do have and will still achieve as time pushes us forward. Thank you for helping to expand on this topic.
In addressing your comments about the bettas raised indoors vs outdoors, while everything you mentioned plays a part, there are still other things that factor into that equation. Sunlight and availability of UV rays, vitamins and minerals found in the water & food supply, and even lack of some vitamins and minerals will also factor in. There is no substitute for a natural environment. We can replicate as much as we want for our own pleasure in the captive keeping of these animals, but we must face the reality that every animal that is raised in a captive environment is going to be at least slightly "different" than if it were allowed to live in a truly wild habitat. You mention that the outdoor fish never had a water change, but that isn't entirely accurate... rain water serves the same purpose as a water change would indoors. Outdoors you mention the algae/green water, but forgot to mention that while the water was nasty looking, it served a
filtration purpose that the fish indoors were not getting. Because it sounds as if it was a pretty bad looking outdoor environment, that would lead me to believe there was enough algae growth in that water to consume waste products more so than in the "clean" indoor habitat. Just because something doesn't look good to us doesn't mean it isn't a good thing for the fish. That algae in the water, while undesirable to look at, also provides live food (that feeds on the algae) in ample supply (food that continues to live, grow, thrive until eaten rather than dying and polluting the water because it wasn't eaten) and even shelter for the fish from UV rays, predators, etc. Because bettas breathe air from the surface, they don't need the clear, clean water that another species would. That is a genetic adaptation in this species of fish for survival, considering their wild "natural" habitat tends to be shallow, murky, "dirty" pools of water. When we
move that indoors and attempt to replicate their needed conditions for survival and breeding, we can't expect to be able to offer them the exact same environment in which to thrive.
Indoors we don't regulate temperature as happens outdoors, which can help protect them from various illnesses, diseases, and parasites in a wild environment. Some bacteria can only live within a specific temperature range, the same applies to fungus and parasites. Exposure to all of these things in a wild environment is also different than captive, which means these fish will respond differently throughout their lives when it comes to sickness/disease, immune system, and even response to medications. There is a wide scale of variation, way too much to put into this already lengthy post.
Before I end I do want to make mention of 1 thing. When the time comes for you to bring the outdoor raised fish indoors and introduce them to a captive environment, be sure to quarantine and watch for signs of parasites, especially if you ever intend to mix/match them with captive raised fish and/or their water supply. When introducing wild and captive bred or raised fish to each other, there is always a risk to both because their immune systems differ as do the things they can be "carrying" with them. Once you begin feeding the fish raised outdoors with prepared food or "man raised" live foods, this will again alter their immune systems because they will experience a nutritional change. This applies to any species of fish, including a tank of all wild fish who come from different areas of the world.
I hope this answers all of your questions. I apologize to the group for such a long post, but it was the only way to be thorough in my answers. If you wish to continue a lengthy discussion about this topic, I am always happy to have an email pen pal, and my favorite topic is anything to do with aquatics.
Dawn
Dawn Moneyhan
Aquatics Specialist/Nutritionist
To learn more about me go to
http://www.helium.com/users/449334
--- On Sat, 7/30/11, haecklers <haecklers@gmail.com> wrote:
From: haecklers <haecklers@gmail.com>
Subject: Re: [tropical fish club] life expectancy Guppies and Neon Tetra
To: tropicalfishclub@yahoogroups.com
Date: Saturday, July 30, 2011, 8:26 AM
Dawn,
This is really interesting to me, what differences do you find between captive-bred and wild-caught fish?
Do you think the differences are because the weaker aren't killed off by predators?
Do you find the runts generally are "off" inside, or can they indeed grow into just as good a fish as the fastest-growing fry? I've heard with bettas you often get the most interesting colors and some good finnage from the runts/slowest growing. Two of our most special (color-wise) bettas were runts
We've got a spawn now that contains 1/4 electric blue jack dempseys. The color has been around awhile, they say, but they were always culled as slow-growing off-colored runts by the breeder. It took awhile for folks to realize they grew into the amazing bright blue-colored and less aggressive jack dempsey that now sell for $50 at 3 inches. The high price is because it is so difficult to actually grow them out to that size since they have a high percentage of deformities.
Could the differences be early nutrition? We raised a few spawns of bettas outdoors and they grew much faster and developed better colors and personalities than the ones raised indoors on live foods with frequent water changes - that despite the fact the outdoor ones NEVER got a single water change - their water was murky green, and they only got fed once a day - the rest of the day they had to find their own food. I'm thinking sunlight, algae, wild insects with the broader access to nutrients may be making the difference. There's that theory of methylation - that access to ideal nutrients at the right developmental time switches the right genetic expression off or on for ideal development.
--- In tropicalfishclub@yahoogroups.com, Dawn Moneyhan <dawnshungryeyes4u2c@...> wrote:The differences in captive bred fish vs wild caught also shows up during necropsy and lab work. While we eliminate the risk from predators by breeding/raising captive, what it does to their immune systems and overall genetics over time can be drastic in some species.Â
>
> DawnÂ
>
> Dawn Moneyhan
> Aquatics Specialist/Nutritionist
> To learn more about me go to
> http://www.helium.com/users/449334
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