The Truth about Fish Stunting

[Coleallensmom]

...it's not just keeping your fish in a tank that is inappropriate in size that can harm them. Overcrowding is just as serious of an issue.

I have a local guy that I sell plant trimmings to. Earlier this year I got four silver Angels from him. They were being kept in a 55gal, however the spawning was so large that the babies were crowded together in the tank. A week ago he brought me another baby from that SAME group still being kept in the same 55 gal tank.

The four large Angels are of course mine. I am sure you can figure out which is the newly introduced sibling..

 

[jetajockey]

Nice comparison photo.

How do you know that the size difference is due to stunting and not some other factor? Genetics and nutrition play a large role also. What about the water quality itself? I've heard that lack of water changes can also cause a problem because of hormones but IDK how true that is.

Not trying to start an argument, but just wondering. I grow out a lot of angels and there are lots of runts so that's what made me think of it. I'm sure an inadequate diet could also contribute to it, I kept some JD's at my brothers house in an outside tub during the summer last year and he only fed them once a day, by the end of the summer they were half the size of the ones I kept at home.

 

[absolutangel04]

That is quite a size difference. I do agree with jeta that fish spawns get runts though. But, I also agree that overcrowding stunts growth too.
How old are they all?
BTW, they are beautiful.

 

[Coleallensmom]

Nice comparison photo.

How do you know that the size difference is due to stunting and not some other factor? Genetics and nutrition play a large role also. What about the water quality itself? I've heard that lack of water changes can also cause a problem because of hormones but IDK how true that is.

Not trying to start an argument, but just wondering. I grow out a lot of angels and there are lots of runts so that's what made me think of it. I'm sure an inadequate diet could also contribute to it, I kept some JD's at my brothers house in an outside tub during the summer last year and he only fed them once a day, by the end of the summer they were half the size of the ones I kept at home.

Unless the entire rest of the spawning are runts, I don't that is the case here. I've seen his tanks..all the remaining babies in that tank are the same size.

I specifically asked him about his feeding and pwc schedule. While he feeds them just as much as I do, he is far more lax with his water change schedule than I am.

I have heard the same about water quality and from what I've seen, I'm inclined to believe it can affect growth to a certain extent. IMO, that is not the only determining factor at play here though... he has one display tank in which he has 2-3 Angels from the spawning in question. Those are considerably larger then those in his 55gal although (admittedly still a bit smaller than mine).

 

[aqua_chem]

Ive heard (dubiously) that the stunting can be caused by excessive fish hormones in the water causing limited growth, but I doubt that is a major contributer. Rather, I side with the nutrition argument. A fish with a health, high protein diet will quickly outpace his brother on nutrifin flakes.

 

[jetajockey]

So the runt theory is nixed, but water change routine is in question along with tank size of course.

Did you find out what kind of food they were eating?

I'm just asking because it really should be narrowed down if possible, I've seen some extremely packed growout tanks, especially in the fish farm setting, but generally speaking the fish seem to be fine, not because of the space but because of the water quality and possibly diet.

Is there any visible signs of stunting? Larger than normal features like the eyeball?

 

[ridewithme38]

I grew up in a modest 1800 sqft house, while one of my friends i went to school with grew up in a home almost triple that size...Me and my two brothers are all over 6' while him and his one brother are under 5'6"

I believe i have just proven beyond a shadow of a doubt that larger homes produce smaller people.....Oh wait, that makes no sense...

My point is, what causes stunting at one point or another has been pointed to everything from genetics to sunlight to nutrients, color, water flow...Why can't we just accept that some fish are just smaller then others?

 

[jetajockey]

I grew up in a modest 1800 sqft house, while one of my friends i went to school with grew up in a home almost triple that size...Me and my two brothers are all over 6' while him and his one brother are under 5'6"

I believe i have just proven beyond a shadow of a doubt that larger homes produce smaller people.....Oh wait, that makes no sense...

My point is, what causes stunting at one point or another has been pointed to everything from genetics to sunlight to nutrients, color, water flow...Why can't we just accept that some fish are just smaller then others?

The people vs fish is a noncomparison other than that there are several factors that contribute to the result.

We have the end result, which is smaller than normal fish. We see what the normal sized fish from that spawning are size-wise, so we can narrow down what caused one group to be smaller than the other, at least somewhat.

I wouldn't be quick to label it one thing or another, but it is worth investigating.

 

[Coleallensmom]

That is quite a size difference. I do agree with jeta that fish spawns get runts though. But, I also agree that overcrowding stunts growth too.
How old are they all?
BTW, they are beautiful.

Thanks..not 100% sure on their age. Approx 10 months old? I've had mine since May.

 

[absolutangel04]

Speaking specificly about the angels, the ones I have seen that have been stunted (life in a 5 or 10g tank with wayyyyyy too many tankmates) have actually looked very proportionate. I was surprized to hear how old the fish were considering the size they were.
Wow, he is pretty tiny for about 10 months.

 

[Coleallensmom]

So the runt theory is nixed, but water change routine is in question along with tank size of course.

Did you find out what kind of food they were eating?

I'm just asking because it really should be narrowed down if possible, I've seen some extremely packed growout tanks, especially in the fish farm setting, but generally speaking the fish seem to be fine, not because of the space but because of the water quality and possibly diet.

Is there any visible signs of stunting? Larger than normal features like the eyeball?

It's a bare bottom tank; He does PWCs anywhere from every other week to every three weeks I believe. The large group are in a 55 gal, his display tank is a 75 gal.

He told me what he feeds them but the conversation was a month or so ago and I don't really remember what it was (I can ask again though).

I've not inspected his juves however the one he gave me seems to be doing fine; just is much smaller in size then his siblings.

 

[Coleallensmom]

Ive heard (dubiously) that the stunting can be caused by excessive fish hormones in the water causing limited growth, but I doubt that is a major contributer. Rather, I side with the nutrition argument. A fish with a health, high protein diet will quickly outpace his brother on nutrifin flakes.

I've heard the same re: excessive hormones. I'd be inclined to think nutrition would be an important deciding factor as well.

 

[Coleallensmom]

Speaking specificly about the angels, the ones I have seen that have been stunted (life in a 5 or 10g tank with wayyyyyy too many tankmates) have actually looked very proportionate. I was surprized to hear how old the fish were considering the size they were.
Wow, he is pretty tiny for about 10 months.

I've not inspected his other juves however the one he gave me seems to act/look normal; just is much smaller in size then his siblings.

Yes, way too small!

 

[Bigpoecilia]

One thing I have observed over the years with my experience in breeding Sailfin Mollies is that all the mollie breeders (livebearer breeders for that matter) have always stressed to me the importance of water changes to reduce the amount of hormones in the water. Especially if you are trying to produce that large sailfin which the males are noted for. It also has an effect on the amount of males you may have in a particular brood, since mollies are known to change their sex. I have no proof of this because I have not done any experiments. But the one thing I have noticed is that you get big robust males (with large dorsals) and large females with regular water changes. When I got lazy with water changes with some broods I got smaller males with shorter dorsal fins and smaller females. I think there is some truth to stunting cause by lack of water changes.

Lionel

Thanks..not 100% sure on their age. Approx 10 months old? I've had mine since May.

 

[Coleallensmom]

One thing I have observed over the years with my experience in breeding Sailfin Mollies is that all the mollie breeders (livebearer breeders for that matter) have always stressed to me the importance of water changes to reduce the amount of hormones in the water. Especially if you are trying to produce that large sailfin which the males are noted for. It also has an effect on the amount of males you may have in a particular brood, since mollies are known to change their sex. I have no proof of this because I have not done any experiments. But the one thing I have noticed is that you get big robust males (with large dorsals) and large females with regular water changes. When I got lazy with water changes with some broods I got smaller males with shorter dorsal fins and smaller females. I think there is some truth to stunting cause by lack of water changes.

Lionel

I've not done experiments either, but as I said previously...I'd be inclined to believe it does have some influence on growth. How much I don't know but as I mentioned, even the angels in his display tank are a tad smaller in size than mine.