The biggest RTC raised in captivity is 160 cm or 5'4", 41 years old (in 2013)

[fishhead0103666]

For the right person this could be carried out. Red tail catfish for example could be used.
Tank A is a wild caught red tail fed the best food available and pristine wanter.
Tank B is a wild caught red tail but fed bad stuff.
C and D are the same except captive bred. The only issue I see with this is genders playing a role in it so you would have to get the same gender to make it a stable study.

 

[thebiggerthebetter]

I presume you are speaking of only the fish purposefully captive bred for ornamental fish trade... because the culls from the fish farms producing food for humans can all be assumed apriori to possess poor genetics, they are the underperformers, culls, dinks, runts, refuse, etc. with slower than expected growth, smaller max size, shorter lifespan, often digestion problems, often malformed in some way but not at all necessarily.

We get a lot of these in our hobby, lots more than people realize.

Just among catfish such examples are
-- TSN,
-- RTC,
-- TSNxRTC,
-- TSNxachara,
-- achara,
-- iridescent shark catfish
-- and all other Pangasiidae, like black ear and paroon,
-- walking catfish
-- and any other Clariidae, like gariepinus,
-- Hemibagrus nemurus and wyckioides,
-- channel and blue catfish,
-- wels,
-- etc.

 

[Backfromthedead]

For the right person this could be carried out. Red tail catfish for example could be used.
Tank A is a wild caught red tail fed the best food available and pristine wanter.
Tank B is a wild caught red tail but fed bad stuff.
C and D are the same except captive bred. The only issue I see with this is genders playing a role in it so you would have to get the same gender to make it a stable study.

Theoretically you could just have two samples, WC and CB, fed exactly the same. It would be best to have several subjects of each to better validate the results, and you'd have to be careful to control their environments so they were all equal.

If i ever perform the study it probably wont be rtc because of the need for so many huge enclosures. I would probably do something like the blue acara, and the samples would be six individuals each in a 75 or something.

 

[fishhead0103666]

Yes I was talking about fish bred specifically for the aquarium trade.
Victor, do you think that with the specifications I have listed that a study carried out could be succesful?

Theoretically you could just have two samples, WC and CB, fed exactly the same. It would be best to have several subjects of each to better validate the results, and you'd have to be careful to control their environments so they were all equal.

That could work but you bring up a good point with the environment. Perhaps an automatic drip system would be best for this?

If i ever perform the study it probably wont be rtc because of the need for so many huge enclosures. I would probably do something like the blue acara, and the samples would be six individuals each in a 75 or something.

Yes, the red tail catfish were just an example. There are plenty of fish that don’t grow as large as they do in the wild, more example in saltwater. I have plans to do something similar to this with gulper catfish within the next few years (hoping for within 3 but possibly 10+).

 

[RD.]

I personally think that you guys are overthinking this.

The cat in question was under a foot when purchased, in 1972, which is 53 yrs ago, and that cat is now 5.25 feet. In other words, besides it's genetic foundation - EVERYTHING done to this fish is part of the end result. What does WC, or captive, have to do with the end result of 53 yrs in captivity? Obviously ALL of this fishes growth & lifespan is based on the past 53 yrs of care. I don't have the slightest clue what Reaper was referring to? Better genetics? Do WC fish typically live longer, or grow larger than their F1 offspring - not in my experience. In fact, IME, many captive fed F1 fish grow much larger in captivity, and most likely live much longer than in the wild, where predators abound, and calories are burned off at a much higher rate, compared to in captivity. The reverse may hold true for large species, such as RTC, which is probably typically due to water quality, and size of the enclosure. This doesn't appear to be an issue at the zoo, where plenty of water is available.

 

[Backfromthedead]

I personally think that you guys are overthinking this.

The cat in question was under a foot when purchased, in 1972, which is 53 yrs ago, and that cat is now 5.25 feet. In other words, besides it's genetic foundation - EVERYTHING done to this fish is part of the end result. What does WC, or captive, have to do with the end result of 53 yrs in captivity? Obviously ALL of this fishes growth & lifespan is based on the past 53 yrs of care. I don't have the slightest clue what Reaper was referring to? Better genetics? Do WC fish typically live longer, or grow larger than their F1 offspring - not in my experience. In fact, IME, many captive fed F1 fish grow much larger in captivity, and most likely live much longer than in the wild, where predators abound. The reverse may hold true for large species, such as RTC, which is probably typically due to water quality, and size of the enclosure.

Overthinking maybe. And while you make good points, any conclusion you draw from what we do know is just conjecture, not proven by science. You of all people should understand that

There is a lot of evidence that suggests, in humans at least, that much of our physiological and mental development takes place in the earliest stages of our lives. Perhaps this trend could be paralleled in some way to fish. Its entirely feasible that the fishes overall growth rate and metabolism could've been heavily, if not completely affected by its environment during the first 12" of it's life, laying a foundation for further growth that an aquarist might never be able to match.

 

[fishhead0103666]

I either watched a show or read somewhere that a crocodile or gator species was conditioned (may be the wrong word) to grow to a certain size once they past a certain size because of the stress they have endured. The young ones now have to deal with predators, humans encroaching on their territory, humans taking fish that they could have eaten, and more. Because of that they grew smaller while the ones that were born decades ago didn’t have to deal with as much and grew larger.
Perhaps this plays a roll as well?
I will try to find the link.

 

[RD.]

Overthinking maybe. And while you make good points, any conclusion you draw from what we do know is just conjecture, not proven by science. You of all people should understand that

There is a lot of evidence that suggests, in humans at least, that much of our physiological and mental development takes place in the earliest stages of our lives. Perhaps this trend could be paralleled in some way to fish. Its entirely feasible that the fishes overall growth rate and metabolism could've been heavily, if not completely affected by its environment during the first 12" of it's life, laying a foundation for further growth that an aquarist might never be able to match.

Proven in millions of tanks around the world, with numerous species, is sometimes good enough for me.

Not with RTC's of course, so certainly that could play out differently - but ...... "Its entirely feasible that the fishes overall growth rate and metabolism could've been heavily, if not completely affected by its environment during the first 12" of it's life, laying a foundation for further growth that an aquarist might never be able to match." ...... could go either way with a WC fish, or captive bred, positive or negative - correct? Just looking at one thing, cortisol levels, could be high or low, for that first part of a wild or captive bred life, entirely depending on the conditions that it was growing in. So again, I think an exercise in futility.

Or am I missing something?

 

[twentyleagues]

Overthinking maybe. And while you make good points, any conclusion you draw from what we do know is just conjecture, not proven by science. You of all people should understand that

There is a lot of evidence that suggests, in humans at least, that much of our physiological and mental development takes place in the earliest stages of our lives. Perhaps this trend could be paralleled in some way to fish. Its entirely feasible that the fishes overall growth rate and metabolism could've been heavily, if not completely affected by its environment during the first 12" of it's life, laying a foundation for further growth that an aquarist might never be able to match.

That is kind of what I was getting at. I think alot of the time in CB grow outs they are fed a staple brand x chow. In the wild while harder to come by they are eating high quality live foods. I think in the first months of life this could have a huge impact on their initial development.
But I could be completely wrong also. Ive seen some breeding setup on YouTube and what not that appears they are feeding good food and have excellent filtration/water quality standards. Ive seen some videos of these hastily dug pits in some places where it looks was if they are living in mud and looks to being fed dog food.
Its just a thought.

 

[Backfromthedead]

I either watched a show or read somewhere that a crocodile or gator species was conditioned (may be the wrong word) to grow to a certain size once they past a certain size because of the stress they have endured. The young ones now have to deal with predators, humans encroaching on their territory, humans taking fish that they could have eaten, and more. Because of that they grew smaller while the ones that were born decades ago didn’t have to deal with as much and grew larger.
Perhaps this plays a roll as well?
I will try to find the link.

Definitely. If an ecosystem can no longer support a vast population of large individuals that may have grown very slowly, the genetics of future offspring may be dominated by those individuals equipped for quick growth, smaller overall size, different nutritional needs, etc. Due to their success in breeding over the others.

One of the studies i extrapolated for my senior thesis related to this kind of shifting ecological trend in the tropical pacific, where over the course of 70-80 years greater numbers of large fish have been caught, but average size of the individual fish has dropped significantly.