paddlefish

[drewdog31]

yes and no

 

[Moontanman]

yes and no

Yes and no what?

 

[Chaz88]

hay chazz88 meby if you keep large fish you would know that fish in captivity never get as big as the fishes in the wild.

Why do they "never" get as big as fish in the wild?

I don't claim to be an expert on paddlefish, so I asked that somewhat open ended question. I must say in general I don't buy the idea that fish don't grow as big in captivity as in the wild, but there could always be a legitimate exception to the rule. I do believe that fish in captivity will grow to their natural potential or to the limits of the life support system they are kept in. Then they will get stunted and eventually die an early death.

I do in fact keep some large fish now and have kept much larger in the past. I believe the ones that did not grow as big as they could have in the wild is because I failed to give them the support system they needed. On the other hand I have kept fish that got much bigger than the average of their wild counterparts. Why? Because they had less competition for food and no threat from predators in my tank.

 

[Moontanman]

I don't claim to be an expert on paddlefish, so I asked that somewhat open ended question. I must say in general I don't buy the idea that fish don't grow as big in captivity as in the wild, but there could always be a legitimate exception to the rule. I do believe that fish in captivity will grow to their natural potential or to the limits of the life support system they are kept in. Then they will get stunted and eventually die an early death.

I do in fact keep some large fish now and have kept much larger in the past. I believe the ones that did not grow as big as they could have in the wild is because I failed to give them the support system they needed. On the other hand I have kept fish that got much bigger than the average of their wild counterparts. Why? Because they had less competition for food and no threat from predators in my tank.

The paddlefish are an unusual situation, i have no explanation for why they stay so small but I do know that fish size is highly variable and most maximum size fish are unusual even in the wild.

Populations of wild fish can vary wildly in size due to many reasons, over population is the usual reason but other factors can come into play. I've been told that day length is a big factor in some fish.

It's a sure thing that pheromones are involved with many fish and with some fish it's synergy of several reasons.

One thing I truly believe is that fish do not have to reach some arbitrary size to be healthy or well kept. I remember visiting a state run hatchery a few times many years ago. They had tank with several small, less than 6" trout in one tank, I was told they were natural dwarfs and were the same age as the huge 18"+ fish in the next tank. Genes were the reason they were dwarfs, the dwarfs turned up at a predictable rate out of the normal fishes.

 

[Chaz88]

One thing I truly believe is that fish do not have to reach some arbitrary size to be healthy or well kept. I remember visiting a state run hatchery a few times many years ago. They had tank with several small, less than 6" trout in one tank, I was told they were natural dwarfs and were the same age as the huge 18"+ fish in the next tank. Genes were the reason they were dwarfs, the dwarfs turned up at a predictable rate out of the normal fishes.

I don't disagre with you. But I do think if the living conditions won't allow them to reach their genetic potential, from dwarf to giant, then the captive environment can be a limiting factor and lead to stunting and a shortened life span. I would also submit that the stunting and inadequate captive environment drum is beat too hard by some, but I rarely comment on it because I think it is better to have people considering such factors than rushing blindly into the O, Pacu ect.. in a 10 gallon tank scenario.

 

[Moontanman]

I don't disagre with you. But I do think if the living conditions won't allow them to reach their genetic potential, from dwarf to giant, then the captive environment can be a limiting factor and lead to stunting and a shortened life span.

Do you have any evidence for a shortened life span on a fish that fails to meet it's maximum size?

I would also submit that the stunting and inadequate captive environment drum is beat too hard by some, but I rarely comment on it because I think it is better to have people considering such factors than rushing blindly into the O, Pacu ect.. in a 10 gallon tank scenario.

I have been stunting fish for many many years, things like photo period, food, and pheromones can and do play a big role in maximum fish size, both in the wild and in aquaria. I have seen no evidence that a fish not reaching it's maximum potential size affects it's life span. Of course I am not talking about a pacu in a ten gallon tank, while I do think that stunting a fish is not a bad thing common sense does need to come into play.

One of my fav fishes was an iridescent shark i dwarfed, it lived for several years, spending it's summers in a large yard pond and it's winters in a 125. The fish was 11" long, it never grew longer despite it being fed the best in live food and commercial food. It met it's demise on summer morning to a Blue Heron who cleaned out the yard pond.

Some fish are more plastic than others in their size, goldfish and koi must be among the most plastic of fishes when it comes to size and the size of the container seems to have a lot to do with goldfish maximum size.

I used to assume that paddlefish and sturgeon would be among the least plastic of fish but it seems to be turning out differently.