Lot's of interesting points here. I'll try and make a few of my own. Personally I don't accept the idea that a stunted fish is necessarily unthealthy. Fish can do a lot of pretty amazing things. There are fish that change from male to female or vice versa as they grow or become dominant. There are male fish that delay expression of male characteristics while in the pressence of a more dominant male. There are male salmon that remain small, stay in the river where they hatched and sneak into nests unnoticed to spawn with normal sized females. Some fish can breathe air. Heck male deep sea angler fish attach themselves to the females body, permanently fuse with it and absorb their nutrients from her.
Perhaps, just perhaps there are environmental cues that we haven't yet figured out, which signal to a fish that growing larger isn't going to be a good investment of it's energy. Now I agree that poor water quality, injury, and illness are probably among those environmental cues, and possibly the more common ones seen in an aquarium, but are they necessarily the only cues? I don't pretend to know what could make a healthy fish stop growing, but I have seen ponds and lakes with seemingly healthy sunfish that are stunted. We did age and length measurements on sunfish from such a lake in a biology class in college. Examined scales under a microscope to get the age. Then we plotted growth rates. They grew about an inch a year for about 3 years then dramatically slowed down topping off at about ~4 to 5 inches. These fish were not emaciated, and they appeared healthy, they just weren't getting big (well okay they were dead so didn't actually appear healthy while we were removing scales, but appeared to have been healthy when collected). I'm sure given other conditions they could get big, but I don't necessarily think they would be healthier, just bigger. This lake also had a population of largemouth bass which were not stunted so I don't think it was a water quality issue.
I don't know if paddlefish specifically can be kept small and healthy, but if they were otherwise going to the garbage I guess I don't see the harm in trying. The worst that will happen is the paddlefish will get to live a few extra months/years, before outgrowing the tank and dying, and the person who bought it will learn the hard way that large fish can and do outgrow small tanks.
I myself have no desire to try and keep a fish as a pet that I know will get too big for its tank and will have to be killed. I don't see it as a problem though if others do. As and example if I can go fishing today and bring home a bluegill for the frying pan tonight, what's the difference if someone else goes fishing today keeps their bluegill in a 20 gallon aquarium for 6 months and then kills it when it gets too big?

Don't know if this applies to a lot of fish, but it's well known in the tropical world that an Oscar will grow to the size of the tank it's kept in. Big tank, big oscar. Small tank, smaller oscar.

All the same, if you're going to keep a fish like a paddlefish, there is some responsibility to get a tank large enough to keep it reasonably healthy, a filtration system that can support it, and understand what it takes to keep a somewhat unusual fish like that alive. I would love to have kept the gar I accidentally netted, but just didn't have a tank large enough. Don't think it could have even turned around in my 75...

Don't know if this applies to a lot of fish, but it's well known in the tropical world that an Oscar will grow to the size of the tank it's kept in. Big tank, big oscar. Small tank, smaller oscar.

All the same, if you're going to keep a fish like a paddlefish, there is some responsibility to get a tank large enough to keep it reasonably healthy, a filtration system that can support it, and understand what it takes to keep a somewhat unusual fish like that alive. I would love to have kept the gar I accidentally netted, but just didn't have a tank large enough. Don't think it could have even turned around in my 75...

I personally don't believe that the tank size will prevent fish to stop growing, its other factors. I've seen bullheads and catfish outgrew tank which supposed to limited their growth.

Don't know if this applies to a lot of fish, but it's well known in the tropical world that an Oscar will grow to the size of the tank it's kept in. Big tank, big oscar. Small tank, smaller oscar.

I must disagree. When I was a teenager, a friend gave me an oscar that he didn't want any more. It was 10 inches and had lived its whole life in a 10-gallon tank.

I must disagree. When I was a teenager, a friend gave me an oscar that he didn't want any more. It was 10 inches and had lived its whole life in a 10-gallon tank.

I also had an Oscar reach close to 10in in a 10g back in the 80's before I knew anything about keeping fish. JOHN 0 It is well known in the Tropical community (once you get away from the kid that works at petco/petsmart) that fish DO NOT grow to there surroundings, what does happen is called stunting which leads to early death, post that on a tropical forum and see the reaction you recieve.

For those of you who say a fish that is stunted is unhealthy and will die young is this just anecdotal or do you have a scientific study that shows this? I would say a 10" Oscar is not a full sized Oscar, I've seen them significantly bigger. I would say a slow fish like an Oscar with reasonable care and plenty of food and high water quality wouldn't be unusual to reach 10" in a 10 gallon tank. I would also point out that there are fish that turn up that are naturally small. I've seen trout in a hatchery that never got beyond 6". The hatchery said it was a natural runt not stunted by lack of anything. The paddlefish in question were natural runts not normally growing fish. I also think it should be said that i would be quite surprised to see a paddlefish that maxed out at less than 24" even for a stunted runt fish. We are not talking about keeping these fish at 3" If you had put 5 Oscars in that 10 gallon do you think all of them would have been 10" a slow fish that needs less room can grow bigger in a small container. The iridescent shark I kept long term only grew to 10" about 1/3 of his expected adult size. i had him for 8 years, in the winter he was in a 125, in the summer a 500 gallon pond, he was eaten by a water bird from the summer pond I kept him in. I think it's necessary to say just how big or small we are talking about stunt a fish to and how big the fish is really expected to get (not world record or some seldom seen maximum size) Some fish are no doubt easily stunted with no effect on their health, gold fish come to mind, others are unlikely to be stunted as much as others. All fish are different and have different possible sizes. i just don't think we need to expect our fish to reach some arbitrary maximum size for them to be healthy and long lived. I would also suggest that maximum size fish are the exception even in the wild rather that the rule. Flat head catfish can get quite large but you seldom see a five foot 150 pound fish even in pristine waters. I really think we should bypass emotions if we are going to discuss this and realize no one is suggesting any and all fish can be frozen at some arbitrary small size anymore than they can be expected to reach an arbitrary large size.

Don't know if this applies to a lot of fish, but it's well known in the tropical world that an Oscar will grow to the size of the tank it's kept in. Big tank, big oscar. Small tank, smaller oscar.

All the same, if you're going to keep a fish like a paddlefish, there is some responsibility to get a tank large enough to keep it reasonably healthy, a filtration system that can support it, and understand what it takes to keep a somewhat unusual fish like that alive. I would love to have kept the gar I accidentally netted, but just didn't have a tank large enough. Don't think it could have even turned around in my 75...

I would agree with you, I might start out in a 75 with a small paddlefish but eventually I would expect to house it in a 3 or 4 hundred gallon tank or a large pond. I really can't see a paddlefish living it's entire life in a small tank. I think some here have assumed that if you start a fish out in a small tank it will have to live in that tank forever. If I had a fingerling paddle fish I would want to start it out in a very small tank so I could make sure it ate and to keep close track of it. Once it settled down i would move it to a 125 or so for a year or more until it started to look like it needed a bigger tank. Or transfer it to a pool or pond. Now having said that i must point out this is just my approach, since the fish would have been killed anyway i have no problem with some wanting to keep it in a small tank for as long as he could keep it alive. I would also point out that taking a paddlefish from the wild is reprehensible and no one should ever do that.

Why make your font more bigger? I believe they already do studies on stunting fish in few species. In stunted fish, the fish being slowly growing but their organs don't stop growing and eventually killed the fish from lack of room for organs to grow. Runts could mean a fish with poor genetics, just like runts in commerical chickens I used to work with. Again nobody's planning to make their fish reach the world record size.
I won't be surprised to see if the paddlefish reached 24 inch long if they received good husbandy. Even runts can grow as nearly all fish never stop growing whole lives but more like slowly.

Your proof got eaten by a bird, it could still growing more in later years anyways. Also we never said that our fish have to reach their maximum size, we just want to see them in the "average" size. Any healthy fish cannot be stop from growing, even with poor genetics and limited food.

Again it VARIES in nature and aquarium too, however if the fish received better care, they will growing and thriving, its nothing you could do to stop fish's growth.

Why make your font more bigger? I believe they already do studies on stunting fish in few species. In stunted fish, the fish being slowly growing but their organs don't stop growing and eventually killed the fish from lack of room for organs to grow. Runts could mean a fish with poor genetics, just like runts in commerical chickens I used to work with. Again nobody's planning to make their fish reach the world record size.
I won't be surprised to see if the paddlefish reached 24 inch long if they received good husbandy. Even runts can grow as nearly all fish never stop growing whole lives but more like slowly.

Your proof got eaten by a bird, it could still growing more in later years anyways. Also we never said that our fish have to reach their maximum size, we just want to see them in the "average" size. Any healthy fish cannot be stop from growing, even with poor genetics and limited food.

Again it VARIES in nature and aquarium too, however if the fish received better care, they will growing and thriving, its nothing you could do to stop fish's growth.

Because I have weak old mans eyes, I honestly thought the fish should grow larger as well but it was eight years old and never grew any more after the first or second year. I do feed my fish good healthy food, live daphnia, live black worms, earth worms, green peas, Hikari micro pellets. In the pond he was fed by me and nature. The pond contained no fish over the winter and was full of insect larvae, crustaceans, and worms. The fish hatchery I went to would disagree with you, they said the runts were genetically small and would never grow past about 6" They said the fish occurred at a predictable rate. I can't remember the percentage but it was low, but since they bred hundreds of thousands of fish they occurred quite often.

Because I have weak old mans eyes, I honestly thought the fish should grow larger as well but it was eight years old and never grew any more after the first or second year. I do feed my fish good healthy food, live daphnia, live black worms, earth worms, green peas, Hikari micro pellets. In the pond he was fed by me and nature. The pond contained no fish over the winter and was full of insect larvae, crustaceans, and worms. The fish hatchery I went to would disagree with you, they said the runts were genetically small and would never grow past about 6" They said the fish occurred at a predictable rate. I can't remember the percentage but it was low, but since they bred hundreds of thousands of fish they occurred quite often.

Its possible these dwarf trout have genetic problems (poor growth genetics from poor broodstock due to inbreeding) or nutrients problems as its not uncommon in hatcheries.

What where we arguing about (Discussing) again? I lost track with all of this spinning in circles....
Does one of those here yapping back and forth care to actually come up with a synthisis of their point to avoid all this circle jerk chatter.

For those of you who say a fish that is stunted is unhealthy and will die young is this just anecdotal or do you have a scientific study that shows this? I would say a 10" Oscar is not a full sized Oscar, I've seen them significantly bigger. I would say a slow fish like an Oscar with reasonable care and plenty of food and high water quality wouldn't be unusual to reach 10" in a 10 gallon tank. I would also point out that there are fish that turn up that are naturally small. I've seen trout in a hatchery that never got beyond 6". The hatchery said it was a natural runt not stunted by lack of anything. The paddlefish in question were natural runts not normally growing fish. I also think it should be said that i would be quite surprised to see a paddlefish that maxed out at less than 24" even for a stunted runt fish. We are not talking about keeping these fish at 3" If you had put 5 Oscars in that 10 gallon do you think all of them would have been 10" a slow fish that needs less room can grow bigger in a small container. The iridescent shark I kept long term only grew to 10" about 1/3 of his expected adult size. i had him for 8 years, in the winter he was in a 125, in the summer a 500 gallon pond, he was eaten by a water bird from the summer pond I kept him in. I think it's necessary to say just how big or small we are talking about stunt a fish to and how big the fish is really expected to get (not world record or some seldom seen maximum size) Some fish are no doubt easily stunted with no effect on their health, gold fish come to mind, others are unlikely to be stunted as much as others. All fish are different and have different possible sizes. i just don't think we need to expect our fish to reach some arbitrary maximum size for them to be healthy and long lived. I would also suggest that maximum size fish are the exception even in the wild rather that the rule. Flat head catfish can get quite large but you seldom see a five foot 150 pound fish even in pristine waters. I really think we should bypass emotions if we are going to discuss this and realize no one is suggesting any and all fish can be frozen at some arbitrary small size anymore than they can be expected to reach an arbitrary large size.

First off I have no emotional ties to this, the fact is I agree with you to a point on the paddlefish because they were set to die anyway, but with that said believing you can keep a fish small in any size tank is ridiculous, you mention flathead catfish being able to attain a certain size and how this is now rare, many factors can cause this including pollutants, food sources, temperature changes, these things do cause stunting and this has been researched (google it I am not going to provide links), the same happens when a large fish is kept in small tanks, toxins build up faster and this has detrimental effects on growth rate..You are using one fish that was not in a controlled environment as your example, my fish tanks are controlled environments a pond is not, regardless of how long it was before you actually put it in the pond is irrelevant, pesticides, herbicides and fertilizers could be present in your pond along with anything else that was deposited there by rainfall these could lead to stunted growth, what other stocking was with this fish in both the original tank and the pond how much food did this fish recieve. Fish hatcheries are IMO not the best source of scientific information as some of them i have been to are extremely overstocked and breeders are often overfed to speed up the growth to attain breeding size.

As I sit here and watch my Oscars in there 90g tank I am wondering why you consider them a slow fish, they are extremely active fish that travel the entire length of the tank several times a minute.
I thought we discussed the fact that just because a fish can grow to 15" to 20" , the normal sizes for adult oscars, doesnt mean all will and mine that are less than a year old have reach 10 and 8in in the course of 10 months recieving once daily or every other day feedings. All fish will be "slow" when under fed, wild animals do not exert more energy than they can afford to replenish so if you are feeding them much less than they need on a regular basis they are going to conserve the energy they have by not being very active.

All fish will be "slow" when under fed, wild animals do not exert more energy than they can afford to replenish so if you are feeding them much less than they need on a regular basis they are going to conserve the energy they have by not being very active.

This is not true at all...(google it I am not going to provide links)

First off I have no emotional ties to this, the fact is I agree with you to a point on the paddlefish because they were set to die anyway, but with that said believing you can keep a fish small in any size tank is ridiculous, you mention flathead catfish being able to attain a certain size and how this is now rare, many factors can cause this including pollutants, food sources, temperature changes, these things do cause stunting and this has been researched (google it I am not going to provide links), the same happens when a large fish is kept in small tanks, toxins build up faster and this has detrimental effects on growth rate..You are using one fish that was not in a controlled environment as your example, my fish tanks are controlled environments a pond is not, regardless of how long it was before you actually put it in the pond is irrelevant, pesticides, herbicides and fertilizers could be present in your pond along with anything else that was deposited there by rainfall these could lead to stunted growth, what other stocking was with this fish in both the original tank and the pond how much food did this fish recieve. Fish hatcheries are IMO not the best source of scientific information as some of them i have been to are extremely overstocked and breeders are often overfed to speed up the growth to attain breeding size.

As I sit here and watch my Oscars in there 90g tank I am wondering why you consider them a slow fish, they are extremely active fish that travel the entire length of the tank several times a minute.
I thought we discussed the fact that just because a fish can grow to 15" to 20" , the normal sizes for adult oscars, doesnt mean all will and mine that are less than a year old have reach 10 and 8in in the course of 10 months recieving once daily or every other day feedings. All fish will be "slow" when under fed, wild animals do not exert more energy than they can afford to replenish so if you are feeding them much less than they need on a regular basis they are going to conserve the energy they have by not being very active.

Maybe slow wasn't the correct word to use, sedentary is better. Oscars can and do stay in one place for long periods as do many catfish, sunfish and such. They don't need a lot of swimming room. a fish like a iridescent sharks needs more swimming room since it is seldom still. I didn't say you could keep any fish at any size in any aquarium i said exactly the opposite. In the wild under ideal conditions not all fish reach the maximum possible size any more than all humans reach the maximum possible size. This shark wasn't the only shark or fish i have observed this in, i said so in more than one post. If a state run hatchery for one species of fish isn't the best source then what would be? my pond wasn't a natural pond it was artificial, and above ground not in ground, no run off, assuming pesticides and other pollutants is disingenuous to say the least, other fish were not affected in any observable manner. None of us can prove this and all we seem to have is anecdotal evidence. I find myself repeating the same things over and over so I am finished with this. I didn't mean to stir up so much rancor about fish sizes but it is obvious that not all fish attain their maximum possible size and we don't know why for sure. alluding to some sort of problem with husbandry of a fish that lives eight years is wrong. I bred lots of fish and I think i pretty much know how to keep fish as well as or better than most. I wanted to understand how this happens in some fish but not others not debate good or bad fish husbandry. I assume most of us already know whow to sucessfully keep fish, Lots of different ways to get to the same goa, no need to micro critique anyone.

This is not true at all...(google it I am not going to provide links)

How about expanding on that..I trust my college professors that worked as biologist in the field..but they could be wrong as theories change all the time but without you giving more input other than a simple statement not backed up by anything I will stand by what I was taught.

by the way I have googled it and from what I can find the theory still hold's true but granted I should have said ectotherms.

Edited by brian1973, 23 November 2008 - 10:25 PM.

How about expanding on that..I trust my college professors that worked as biologist in the field..but they could be wrong as theories change all the time but without you giving more input other than a simple statement not backed up by anything I will stand by what I was taught.

I'll trust me, being a Biologist in the field, to say that "all fish become sedentary just because they are underfed" is Bunk.... Look up any number of fish energetic studys and you will find this will be consistently false.
And please remember...(google it I am not going to provide links)

by the way I have googled it and from what I can find the theory still hold's true but granted I should have said ectotherms.

Care to actually source this?

Just to put my 2 cents in..... look at the life cycle of brook lamprey. Probably the greatest expenditure of energy (mating) occurs during the final life stage, when they no longer have a functioning digestive tract.

Just to put my 2 cents in..... look at the life cycle of brook lamprey. Probably the greatest expenditure of energy (mating) occurs during the final life stage, when they no longer have a functioning digestive tract.

My apoligizes I may have mistated , I was speaking in general, there are always exceptions to every general rule.

Moontanman..sorry if I sounded harsh with any of my comments, with text it is difficult to express tone, and as for not providing links I dont have time to do so, if you would like me to at a later time PM me and I will be happy to give you links to environmental factors that lead to stunting.

Edited by brian1973, 23 November 2008 - 10:53 PM.

Just to put my 2 cents in..... look at the life cycle of brook lamprey. Probably the greatest expenditure of energy (mating) occurs during the final life stage, when they no longer have a functioning digestive tract.

One of the very reasons I'm bringing this up...

For that matter there are many other species that will expend great amounts of energy just to receive very little for their effort and this does not make them slow down, if anything it increases their energetic output.

One of the very reasons I'm bringing this up...

For that matter there are many other species that will expend great amounts of energy just to receive very little for their effort and this does not make them slow down, if anything it increases their energetic output.

Generally speaking..that is due to the ability to store energy for other purposes such as reprodution etc..correct? Once that energy reserve is used they typically die correct?