Myth or Fact??

True for goldfish. My science fair project was two 1 inch goldies, one in a 2g bowl, one in a 1g. I waited like 2 months and the 2g bowl one was 40% bigger. They are now happily residing in a 75g pond.
 
True for goldfish. My science fair project was two 1 inch goldies, one in a 2g bowl, one in a 1g. I waited like 2 months and the 2g bowl one was 40% bigger. They are now happily residing in a 75g pond.

No offense, but that's not exactly worthy of a scientific journal.
 
jpappy789 - I think you're right that it was salmon. In my younger days I once grew out a texas cichlid to 10" in a 20 gallon high with massive frequent water changes (something I would never think of doing today).

We still need proof that smaller tanks lead to fish putting out a hormone that limits growth.

Pirahna86 - were water parameters exactly the same at all times (which would have required double the number of water changes for the 1 gallon fish)? I'd bet water quality is the issue not hormones.

The 75 gallon vs. 125 gallon situation is much more interesting...be curious to know if the fish were all the same style of goldfish, water parameters, etc. Too bad they weren't kept permanently in the smaller space to see if they were going to stay smaller or just grow slower (and what the water param's for both tanks were in the long term).

Eric
 
false. if a tank is maintained so that new water is introduced very frequently, chances are the fish will grow to its normal size. a fish in a very large tank will not grow larger than its adult size though; a neon will not reach 6 inches long because it is the only fish in a 500 gallon tank.
 
a fish will out grow its surroundings to its max size IMO
 
Pirahna86 - were water parameters exactly the same at all times (which would have required double the number of water changes for the 1 gallon fish)? I'd bet water quality is the issue not hormones.
Yeah, I did a 90% water change twice a week on the one gallon and once a week on the two. They were each fed one 'goldfish crisp' twice a day.
 
I believe the study included growing salmon in very tight spaces with water constantly flowing over them...wish I could find it to verify that though...

i read that study as well cant for the life of me find it, however i know they did it and Texas A&M. But the study aside the only thing that truly limits the growth of the fish is water quality assuming it is being feed a healthy diet
 
i read that study as well cant for the life of me find it, however i know they did it and Texas A&M. But the study aside the only thing that truly limits the growth of the fish is water quality assuming it is being feed a healthy diet


Genetics are something that rarely enters this discussion. In any given brood, there are bound to be outliers on both ends of the size spectrum. Not all fish have the genetic potential to reach the largest size a given species is capable of. I have read about not only discus, but a variety of livebearers releasing growth inhibiting hormones, but am too lazy to dig up any links atm. Also, I think it's more a function of reducing competition for food than it is about controlling size to fit the surroundings.
 
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