This info about fish only growing to the size of their tank is wrong...
based on.......?? care to elaborate??
Jeo- I understand your points and they are good ones. You also touched on some vital points regarding releasing and cruelty, but 20+ yrs of owning large fish only has shown me otherwise (as far as the "turning around" theory). Have you ever seen a fish that can't turn around in a tank? No. I haven't either. Actually, I have, an Arrowana, but it was put in the tank when it was already too big.
And they do "turn off", much like the switch you described but they can also be "turned on" (stop it,lol) again also. Ex: Raised an Oscar from a baby in a 50g. He reached his full size in roughly 2 yrs. He lived in that tank for another 4 yrs. When I rescued another Oscar, a 5 yr old, I gave the 6 yr old to a friend with a 125g. He grew another 1-2 inches and added weight extremely quickly and then growth stopped there. That fish is now going on 12? 13 yrs old? and hasn't grown again since he was introduced to the tank. Either has the 5 yr old I adopted which came from the same size tank he is in now. They are happy, healthy, and not growing. Genetically, they are programmed to grow every day of their lives, PROVIDED THEIR ENVIRONMENT ALLOWS THEM. (that can also be related to fish in the wild, i.e. not enough food, etc)
As for the bioload, absolutely, large fish require more care and water balancing but diet plays a large part in that also. Another trick is to keep the tank as cool as possible, thus slowing the metabolism. Driftwood also helps to balance abnormalities in the water, a must for large fish.
Now, I'm no rocket scientist and I'm not a biologist, but I did stay in a Holiday Inn last week so,... ;D
This might be a good topic to throw at Mr Lusk, a real fisheries biologist. I'll link him and he should reply if he has the time, but it is spring, his busy season, so it may take a bit
I'm not claiming to be the know all on this stuff, I just have a lot of personal experience. Please don't take me as cocky, I know when I write, I can come off that way but I love nothing more than to be proven WRONG,....learning is essential and I care about my pets, I want to give them the best care I can.