Myth or truth? Does tank size stunt fish growth?

I have been told by many many many many people on here and eveywere else especially when I post about my goldfish in my 40 gallon aquarium they always say....
I'm over stocked. My fish will be stunted
I would like to see the truth behind this... Like the science or what ever.
Ive been told it's not about quantity but about quality, so let's say you have a extremely well kept 40 gallon aquarium with 5 lets say goldfish. Would these fish become stunted due to size? Or do they get stunted due to quality? I think it's the latter of the two. Quality.... So if y'all got any suggestions or comments or what ever just say some stuff below..

 

Yes in fact space does play a role. And it just so happens enough goldfish have been kept to generate an average growth rate:





As they grow water quality becomes increasingly difficult to keep clean which also contributes to stunting of growth.

 

Goldfish are generally a poor choice for home aquaria, with exceptions to large tanks with fancy goldies. Comet and common goldfish, as well as koi, are better suited to ponds. If you truly care about the well being of your fish I encourage you to reconsider your stocking choices.

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The point brought up on one of them is that in order to keep water quality very good in a tank that is much too small, you'd have to do multiple large (90%) water changes daily. This in turn causes stress to the fish, which can also stunt growth. Therefore, it's a viscous cycle.

Edit: Love the link! Someone beat me to the SF link as well, but I don't think the others were posted.

 

Goldfish, if kept in too small a tank will send out chemicals that stunt their bone growth but not their innards, their innards will keep growing despite their stunted bones eventually killing the poor Goldfish.
as far as I know this only applies to Goldfish.

 

I've always doubted this as i've seen fish that can barely turn around in their tank they were so large. I would never want to keep fish like this as watching them as they look in their natural habitat is why I keep fish in the first place. I've killed many fish due to my ignorance and sometimes bad judgments, but I TRY to provide a healthy environment, we owe it to our pets.

 

Welcome to Fishlore! Sorry for forgetting

 

Yes, welcome to fishlore!

 

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