Fish size

A constant food supply, lack of energy expenditure and a winter cooling period can all increase a captive fish's growth IMO.

(Note slightly edited quote)

All of these things can greatly decrease a fishes lifespan as well.... Therefore cutting short there growth.....

Don't you believe that if you're going to be keeping an animal it should be done so properly?

Who says what is proper?

Don't you believe that if you're going to be keeping an animal it should be done so properly?

I think I am doing so properly, if you think any or even most of the fish you keep are better off in captivithy then you are violating your own morels!

I'm not speaking of aquarium books, I'm speaking of "fishes of" books for NA natives.

Yup. According to "Inland Fishes of NY" our states largest green sunfish specimens are 4". The one I have is 9".

Yup. According to "Inland Fishes of NY" our states largest green sunfish specimens are 4". The one I have is 9".

sunfish vary greatly in size over much of their range, the book probably gave an average size, even if it didn't you still don't provve anything with one fish. Itr could have been a sterile giant.

I think I am doing so properly, if you think any or even most of the fish you keep are better off in captivithy then you are violating your own morels!

Did I say you weren't?

Who says what is proper?

Common sense in this case.

All of these things can greatly decrease a fishes lifespan as well.... Therefore cutting short there growth.....

Captive animals typically live longer. I know you know that.

sunfish vary greatly in size over much of their range, the book probably gave an average size, even if it didn't you still don't provve anything with one fish. Itr could have been a sterile giant.

It was just an example to illustrate teleost's point about regional books.

various genus

You'll have to be a lot more specific than that, pacu? goldfish? Paddlefish, alligator gars, sturgeons, cobia?

Usually very young

usually? qwhich ones were young and which ones were old?

Until death (various age) but not terribly longer than wild expectancy

what is wild expectancy, I've kept Cardinal tetra's for five years when in the wild they only live for a year or so.

Usually 8:1 to 10:1

aquarium books are notoriously inaccurate

I'm not speaking of aquarium books, I'm speaking of "fishes of" books for NA natives.

None the less a record fish is not the norm, most fish attain sizes m uch less than record fish.

Did I say you weren't?
Common sense in this case.
Captive animals typically live longer. I know you know that.

Common sense based on what? yours or mine or Jim bobs? Proper husbandry of fishes is not a dogma it is quite elastic in application.

And no it is not really true captive animals live longer. While a longer life span does occur it is really not any more common for this to occur than for a fish to live it's natural lifespan. (And given most captive environments the lifespan is much shorter than even the wild average all to often)

None were old. All were young but usually very young.
Wild expectancy is based on averages compounded scale/bone research by biologists.
I'm not saying I know everything but it seems I've had an astoundingly high rate of particularly large fish when kept in the 8:1 to 10:1 range. I doubt I'm the only one.

It seems much of your focus in this topic is based on tropical fishes. Perhaps this topic would be better suited for a tropical fish forum.

Common sense based on what? yours or mine or Jim bobs? Proper husbandry of fishes is not a dogma it is quite elastic in application.

It is common sense that if you intend on keeping a fish that is commonly known to reach a large size that you don't put it in a tank that is an improper size. By improper size I mean one unable to dilute the fish's waste in conjunction with your water changes and one unable to allow the fish some room to move about.

And no it is not really true captive animals live longer. While a longer life span does occur it is really not any more common for this to occur than for a fish to live it's natural lifespan. (And given most captive environments the lifespan is much shorter than even the wild average all to often)

Well I guess in cases where you keep the animal improperly....

None were old. All were young but usually very young.
Wild expectancy is based on averages compounded scale/bone research by biologists.
I'm not saying I know everything but it seems I've had an astoundingly high rate of particularly large fish when kept in the 8:1 to 10:1 range. I doubt I'm the only one.

It seems much of your focus in this topic is based on tropical fishes. Perhaps this topic would be better suited for a tropical fish forum.

Most of my focus is around the latest fish I have done this with, I've concentrated on breeding crustaceans in recent years and this didn't seem to be a large concern until certain quarters started giving me a hard time about stunting fish. If you have read these threads you'll find that some native fish keepers have found the same thing. Please explain the 8:1 10:1 ratio you keep mentioning. If you think this thread isn't productive lets end it. Personally I think that since a great many of the native and tropical fish we keep are subject to the same rules and conditions in some way or another it has great relevance

Edited by Moontanman, 09 March 2008 - 08:59 AM.

This entire thread to me looks like you're just trying to look for personal justification to stunt large growing species. I hope this isn't the case.

This entire thread to me looks like you're just trying to look for personal justification to stunt large growing species. I hope this isn't the case.

Not at all, I am just trying to get people to give some thought to the fact that many of the fish we keep should have been destined to grow much larger in the wild than they do in our aquariums no matter how well we keep them. We all dwarf fish by confining them (less you are rich and can buy 3000 gallon aquariums) What is important is not how big the fish could get but how well we keep the fish and how much effort we put into meeting their needs with our regular sized tanks. To be honest my experience with dwarfing natives is practically non existent. I keep only small fish like darters, madtoms, sculpins, silversides, and other small fish. (except for the pet flathead I had and was killed by a power failure). I had taught it to come to me on demand and eat from my hand and it was only a few months old. Flathead catfish can be very smart fish and make good pets much like the red tailed catfish popular with tropical fish enthusiasts. It destanation was intened to be a large yard pond when I could call it up to be petted and fed to amze my guests.

Not at all, I am just trying to get people to give some thought to the fact that many of the fish we keep should have been destined to grow much larger in the wild than they do in our aquariums no matter how well we keep them. We all dwarf fish by confining them (less you are rich and can buy 3000 gallon aquariums) What is important is not how big the fish could get but how well we keep the fish and how much effort we put into meeting their needs with our regular sized tanks. To be honest my experience with dwarfing natives is practically non existent. I keep only small fish like darters, madtoms, sculpins, silversides, and other small fish. (except for the pet flathead I had and was killed by a power failure). I had taught it to come to me on demand and eat from my hand and it was only a few months old. Flathead catfish can be very smart fish and make good pets much like the red tailed catfish popular with tropical fish enthusiasts. It destanation was intened to be a large yard pond when I could call it up to be petted and fed to amze my guests.

Well in that case can't you agree that if we intend on keeping a large species we should prepare for the average size it is known to reach and not the size it may reach?

Well in that case can't you agree that if we intend on keeping a large species we should prepare for the average size it is known to reach and not the size it may reach?

No, not knowing what I know now, I think we should first investagate why somefish dwarf easily and some don't so we can avoid the ones that don't. Most large fish are just assumed to out grow their tanks no matter what you do. Information is always better than ignorence. Knowing the whys, hows, and what could avoid a lot of misery on the part of the fish as well as the owners.

No, not knowing what I know now, I think we should first investagate why somefish dwarf easily and some don't so we can avoid the ones that don't. Most large fish are just assumed to out grow their tanks no matter what you do. Information is always better than ignorence. Knowing the whys, hows, and what could avoid a lot of misery on the part of the fish as well as the owners.

I'm sorry but I cannot agree with you based on your one example of an iridescent shark not growing beyond 10". I can think of many cases where iridescent sharks outgrew their tanks, proof that they don't "dwarf easily". I think it is ignorant to assume that because it happened once it is safe to intentionally try to stunt others.

Stunting is caused by several factors, which have all been mentioned here (large population, limited space, water quality, feeding, etc etc). If a fish is stunted in captivity, it's because it isn't getting the conditions it needs to lead a normal, healthy life. Just because a fish can and will stunt under certain conditions doesn't mean you should make it and it's healthy. Stunted fish don't live as long and are much more prone to disease. You said it doesn't matter how big the fish could get as long as we do whatever we can to provide correct conditions, but that includes giving it a tank that can give it enough room to reach its max size. That's part of providing a fish with its needs. Why would you want to stunt a fish? If you can't get a large enough tank and provide it with the conditions it needs to thrive (not just survive), then you shouldn't get it.

Most of my focus is around the latest fish I have done this with, I've concentrated on breeding crustaceans in recent years and this didn't seem to be a large concern until certain quarters started giving me a hard time about stunting fish. If you have read these threads you'll find that some native fish keepers have found the same thing. Please explain the 8:1 10:1 ratio you keep mentioning. If you think this thread isn't productive lets end it. Personally I think that since a great many of the native and tropical fish we keep are subject to the same rules and conditions in some way or another it has great relevance

I don't see a ton of value discussing wild size vs. captive size of iridescent sharks on a native fish forum. I've never seen one in the wild and I suspect few on this forum have.

My reiteration of ratio is not a study but merely an observation. In short, I've noticed that many fish with lots of room tend to get larger than books/wild specimens I've encountered.

I guess I'm trying to offer some thought that home care does not require stunting. This just leads us back to the circuitous debate of ethics. As we know each individual has a different ethical threshold making this topic a bit of a hot button issue but not valueless.

It is common sense that if you intend on keeping a fish that is commonly known to reach a large size that you don't put it in a tank that is an improper size. By improper size I mean one unable to dilute the fish's waste in conjunction with your water changes and one unable to allow the fish some room to move about.

That is not common sense that is good ethical concern mixed in with appropriate fish husbandry.. I do not think anyone here is saying put a whale shark in a 20 gallon. What I am saying is there are conditional factors to take into account when housing any fish, you can not pigeon hole this into a blanket rule. What one may say is an improper tank size, someone else may be spawning their fish in. We really are not in disagreement here Arthur, I do know what you are saying, I do not disagree with you, but in saying it in a vague manner one can come up with 40 different exclusions that test it. Hence it becomes a dogmatic truism that is not exactly encompassing of all species needs or situations. Loads or Anecdotal and empirical information also clearly states that certain species do not reach sizes in captivity that they do in the wild. With a clear knowledge and understanding of the mechanics of fish growth and physiology (on a species basis) some of these hobby truisms really are kind of silly...(in some cases actually detrimental)

Well I guess in cases where you keep the animal improperly....

Again this is not true... Fish do not always live longer in captivity when compared to their wild average even when kept properly.. Some might, I'm not arguing this, but this is not a fact. Some species in captivity will burn out much faster than they do in the wild just because conditions are too good. Some good examples of this are with some Minnow species, Killifish and Livebearer species and of coarse my favorite the Lamprey .. Again you can not blanketly say all species will react to fit the same pigeon hole we give them...