Stunted fish?

[Zander]

I work at a fish store and many people will come into the store and mention the fish in their tank. Every couple weeks or so someone will mention a fish that isn't nearly full grown, and then mention that they've had it for many many years. For example today someone mentioned they had a 2 kissing gouramis that were about 3 inches, and that they'd had them for 4 years. I've never been sure as to why these fish aren't growing to their maximum size, or even close to it, in such a long time. It always prompts me to ask about tank size, feeding schedules, etc., there never seems to be anything wrong with what they're doing. Sometimes the tank might be a little small, but not so small it should be effecting their size. It's not just kissing gouramis, in recent weeks I have had this same conversation about angelfish that never got more than 2 inches long, and again about a chinese algae eater that never got more than 3 inches.

Why do these fish not get bigger? Any guesses as to what is stunting their growth? Or is there a smaller breed of these fish that I am not aware of?

[Rocksor]

Not enough water changes.

[Sandz]

Bad quality condition is my guess. Every single situation is individual though... I have seen blue gill in 10 gallon tanks breed (some kid in college did a science paper on it)... fish are miraculous things and can do many things.

[Crispy]

while I agree with all of the above;

another thing is that like humans, not all fish have the genes to grow to maximum size.

[ddavis1979]

Also keep in mind that fish stories are exactly that....fish stories.

Some people are terrible at estimating size or reading a ruler. Other times people think they have a species that they dont. Just assume that most of what you hear is partially true :)

Some fish, such as angelfish, can be stunted by water quality and tank size. And like previously said, not all fish will reach maximum possible size just based on diet and genetics.

[Honey Badger 1]

Some of the hormones released by fish will stunt other fish's growth too I believe. Here is a piece of a pretty good lecture and the lecture notes from a knowledgeable person about stunting, slow growth, and not growing to potential size. http://www.badmanstropicalfish.com/s...t_3-12-04.html

[UncleWillie]

while I agree with all of the above;

another thing is that like humans, not all fish have the genes to grow to maximum size.

I agree with Crispy. Although there is tons of information out there on stunting, the max size of fish is just that - max size. We don't say all humans reach 8'3'' because that is the maximum reported height. Many fish total lengths listed on websites can be misleading. I personally like it when a range of average sizes is included (e.g., Average adult size: 3.5''-5''). A healthy fish of one sex, genetics, and condition may be well below that of another fish of the same species with different sex, genetics, condition, etc.

[Allecto]

Also keep in mind that fish stories are exactly that....fish stories.

Some people are terrible at estimating size or reading a ruler. Other times people think they have a species that they dont. Just assume that most of what you hear is partially true :)

Some fish, such as angelfish, can be stunted by water quality and tank size. And like previously said, not all fish will reach maximum possible size just based on diet and genetics.

This, plus people are often inaccurate in time estimates. My sister has angels she swears she's been trying to get to breed with no luck for three or four years now. I distinctly remember buying them with her less than a year ago.

[Lady Hobbs]

I've also heard of people who's fish were small and they never seemed to grow until they went into a larger tank and suddenly they have a big growth spurt. I do believe in stunting simple because if an Oscar, that is always known to be large, remains 4" year after year, there is no other explanation for it.

In the case you have mentioned with the two kissing gourami's, I very much doubt they would have two fish known to grow to 12" and both only ended up at 3".

[Zander]

I've also heard of people who's fish were small and they never seemed to grow until they went into a larger tank and suddenly they have a big growth spurt. I do believe in stunting simple because if an Oscar, that is always known to be large, remains 4" year after year, there is no other explanation for it.

In the case you have mentioned with the two kissing gourami's, I very much doubt they would have two fish known to grow to 12" and both only ended up at 3".

I am pretty sure they mentioned that the kissing gouramis were in a 40 gallon, but it might have been a 55. While that is small for a 1 foot one, it isn't 'stunt them to stay only 3 inches' small. 3 inches in a 40 gallon is plenty of room. They shouldn't have started to be cramped for a few more inches.

Also the angelfish I remember was in a 25 gallon. Again, too small for a full grown one but for a 2 inch one that shouldn't be stunting it so much. At least it doesn't seem like it should be.