Fish only grow to tank size - a myth?

[ThaddeusW]

Today I was told by one of our workers who used to have an aquarium that fish only grow to the size of the tank. So the bigger the tank the bigger the fish will grow. Sounds like a myth to me. He was trying to convince me that the Pacu's won't grow because the tank is too small. So is this a Myth or does it apply to certain fish and he misunderstood the phenomenon?

[Amazon]

Its just a myth. The fish's size will get stunted and it will die.

[robflanker]

Absolute myth

[Cristoff]

Try putting the same pants on that you wore in elementary school. :ssuprised:.

Not only a myth, but a tragic bit of misinformation that would cause the fish incredible stress and ultimatley death.

[doug z]

I've seen plenty of miserable 15-20" plecos in 25g tanks... :(

[Northernguy]

I've seen plenty of miserable 15-20" plecos in 25g tanks... :(
So have I! I beleive it is a myth!
Please don't be a Mythbuster and test it out!

[smaug]

Its true to a point.True because many times people who keep large growing fish in small tanks also tend to be ignorant about proper fish keeping.Thus the fish are unhealthy because of many factors including poor water conditions,insufficient food lacking in any real nutrients.This all leads to a fish that is stunted to to poor keeping skills.A fish gets as big as it can get if kept healthy and well nourished,thus 18" fish in a 24" tank.

[Lab_Rat]

A myth, but you can significantly stunt their growth keeping them in too small of a tank. They'll be deformed and much shorter lived than a properly housed fish.

[thatcichlidguy]

There is a certain validity to the comment, but it's kinda the other way around. It isn't that if you keep a big fish in a small tank it will only get as large as the tank will support, but more like if you put little fish in a big tank they have a tendency to grow a bit bigger than if kept in smaller confines.

There are actualy a few species (very few) that do support the small tank theory but you could count all of them on one hand and not use all your fingers before coming to the end of a very short list. Those species do infact only grow in proportion to their tanks without any real health issues, but I'm not listing them out of a sence of moral obligation. I don't want to encourage the practice or any experimentation with it. It's just bad mojo.

[ThaddeusW]

Thanks everyone for clearing this up. I figured it to be a myth.

[mac]

Its true to a point.True because many times people who keep large growing fish in small tanks also tend to be ignorant about proper fish keeping.Thus the fish are unhealthy because of many factors including poor water conditions,insufficient food lacking in any real nutrients.This all leads to a fish that is stunted to to poor keeping skills.A fish gets as big as it can get if kept healthy and well nourished,thus 18" fish in a 24" tank.


I agree with you on this. IMO it is a part myth.
More so when it is in regards to water quality food nutrients and tank size to the fish's size and health. Along with the species.

IMO it is a myth depending on the fish.

mac

[kennedpa]

Sorry folks.... IMO is truely depends on a number of variables.

1) Filtration
2) Water change as some fish and plants let out an enzyme that stunts growth
3) I have had a pleco for 10years and 4 inches in length...happy as not to mention my clowns of 5 years and 5 inches in length.
4) TOTALLY depends on the type of fishies.... some do defy and grow regardless..
5) Causing stunted growth = MYTH.... fishies and plants will only grow to the environment variables... If a fish is stuck in a small body of water it will only grow/adapt accordingly and will not know anything better.....IMO

[Wild Turkey]

Its true to a point.True because many times people who keep large growing fish in small tanks also tend to be ignorant about proper fish keeping.Thus the fish are unhealthy because of many factors including poor water conditions,insufficient food lacking in any real nutrients.This all leads to a fish that is stunted to to poor keeping skills.A fish gets as big as it can get if kept healthy and well nourished,thus 18" fish in a 24" tank.

Good post, agree

They will grow "to the size of the tank" in the same way a I would still grow if I lived in a dog crate, not very well.

[red eyes]

good on you for sniffing that one out oh-so quickly!
good luck with the sadly many many more out there =)