On a common myth about stunting.

[Bignose]

Based on other threads on the forums, I am going to open up this discussion once again:

I am interested in finding real, first-person, actual experience proof of the oft-repeated warning about stunted fish. Specifically, the advice and warning that many, many people give that stunting a fish "causes its organs to keep growing, while its body stops growing, resulting in a deformed fish from the bulged organs.

I am not arguing that stunting does not exist, and I agree that it can have some dire consquences on the health of the fish. The lifespan and health of a fish kept in a too small tank is seriously comprimised. However, the bulging organs theory is repeated a lot, but I have never seen proof.

I do not want, friend-of-a-friend-had-a-stunted fish sotries, I do not want, well so-and-so on the Internet/chat board/webpage said so, I do not want LFS employee/owner/customer said so.

I do want proof that the organs keep growing, and this will probably require some brave soul to perform an autopsy. Not just some brave soul, but a knowledgeable scientist who will know what the normal fish organs are meant to be, and that the bulges from a case of stunting are not tumors or infections or other diseases that the fish will be more prone to b/c of the stunting. I want real proof that stunting, and only stunting, has caused bulging organs.

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The reason I ask is that bulging organs, to me, does not seem to be the way nature works. Stunted populations occur all the time in nature -- limitations on food or pollution in the native waters frequently result in populations that are smaller than norms. Predation can also be a common cause. Sport fishermen know this when the state wildlife and fishing commissions restrict fishing in a lake or stream in order to give the populations a chance to recover.

In fact, long-term stunting is the reason we have the dwarf varieties of some of our favorite fish: dwarf gouramies, dwarf cichlids, etc.

Finally, from "Development and aging of the liver and pancreas in the domestic carp, Cyprinus carpio: From embryogenesis to 15-year-old fish" by Fishelson L and Becker K in ENVIRONMENTAL BIOLOGY OF FISHES Vol 61 Issume (1) pages 85-97, 2001,

"In 15-year-old experimentally stunted fish (110-120 mm TL) the liver and pancreas resemble those of juvenile fish appearing much healthier than those of 8-10 year old large carp from commercial ponds. "

Sure, those are only a few organs and a general assumption about all the organs cannot be completely made completlely accurately, but the liver is a fairly sensiitve organ since it does a lot of the housekeeping of the fish's immune system.

Here is another from "Effect of stunting of juvenile bighead carp Aristichthys nobilis (Richardson) on compensatory growth and reproduction" by Santiago CB, Gonzal AC, Aralar EV, Arcilla RP in AQUACULTURE RESEARCH Vol 35 Issue (9) pages 836-841, JUL 23 2004:

"The carp stunted for 6, 12 and 18 months showed growth compensation, although their weights and lengths were slightly lower than those of the control fish. The body weight and length of fish stunted for 24 months were the lowest throughout the rearing period. Sexual maturation occurred only in the control fish and those stunted for 6 and 12 months. However, the onset of gonad maturity was delayed significantly (P<0.05) in males stunted for 12 months and in both groups of stunted female fish. "

Stunting delayed the development of the fish, but no mention of bulging organs or other deformities.
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I believe that some of this comes from the knowledge that teleosts (bony fishes) are considered to have indeterminate growth, that is, they continue to grow over their entire lifespan. However, as some point in their lives, they devote some, and usually most of their resource intake into reproduction -- generating eggs and maturing their sexual organs. In almost every case, this results in a sigmoidal growth curve: slow at first as fry can only take in a certain amount of food, then rapid in their first year(s) as growth is dominant, then almost all resources get devoted to reproduction related activities.

Ultimately, why would nature allow the growth rates of the skeleton and the organs to be different?!?

So, I suppose I have dropped the gauntlet for anyone who has proof. I am not arguing to go ahead and stunt a fish in a small tank, but I do not think that overstating the effects and using effectively scare tactics of telling people that "your fish's organs will explode!" is fair, either. I have a very open mind, and would like to see some proof for the other side of the argument. At this point, I can really only find hearsay and rumor.

Thanks

 

[gaya]

Yea fish can be stunted, really anything can be stunted but the whole organs growing larger than the musculoskeletal system is weird. I think it is a myth as well. I’ve never found a credible source providing information about it. Though I wonder if the tale may have been started due to diseased organs that were just swollen.

 

[xanthianacid]

When we first got our son's community tank (before which we were novice betta and minnow only pet owners (wont say fishkeepers because we weren't).
My son had been asking well over 6 months for a fish tank for christmas. So we'd kept our eyes out and about the end of November we sighted a good offer - fish and whole set up just over $100 AUD (they are the all inclusive curved perspex kind with inbuilt filter, light etc. It is taller than standard and a little fatter than standard - just imagine a square OK? The fish he gave us was an angel, tetras, (now jogging my memory), guppys, RTBS and there were other fish in there too. He took one fish out (can't remember what), and the length of wood.

Back to the point it was about a 30 gallon. He said he'd had the tank set up about 6 months. The Angel in there was medium sized at this stage. He had huge dorsal and anal fins though, he probably tripled his size because of them or more.

We left him in there as we didn't get another tank for another couple of months. He remained that size always, but there was no bulging - he was as thin as the later angels we got, but unbeknownst to us when we got him he'd surely been stunted. He seemed normal and wasn't until he was savaged by another fish that he died, depressed. I miss him he was a gorgeous zebra.

 

[henry2703]

i have a japaness koi pond at home....

As you would have known that koi feeds vertically.... and if the pond is not deep enough, the koi will not grow to its full potential length....

well... my pond is not deep enough... so my kois kind of like stop growing after about 1 foot in length.... as compared to some of the 2-3 feet lenghth i've seen.... So i concluded that my fish is stunned in its growth....

and... as far as human eyes can see.... there is no abnormal buldging of any organ caused by internal organ deformity....

but please don't ask me to cut my fishes up to check

This is my first hand account... and not a friend of a friend of a friend's grandmother's neighbour' sister-in-laws' prime minister's daughter's friends little son....

hope this helps.....

 

[Synirr]

I think the whole "organs keep growing" thing is a total myth. Back when I was 7 and knew nothing about fish, my mother and I kept a couple of common goldfish in a 10 gallon. They never got larger than about 5 inches, but neither did they look bulging and disproportionate. They did, however, die at about 8 years of age, which is relatively short by goldfish standards, as I understand it.

While I don't think the organs continue to grow even though the fish is stunted, I do think it's possible that stunting can slowly cause organ failure and that stunted fish do normally have a shortened lifespan.

 

[NinjaSmurf]

I think there is a lot of stunting going on, just look at the fish index. You see all sorts of fish where they are supposed to reach 'blank' amount of inches/feet in the wild, but 'rarely grow this big in an aquarium'. Therefore, we stunt some fish all the time, it's just not as noticable.

And I saw a commercial with a woman on a raft with two koi swimming below her. They had to be at least six feet long, they were longer than her or the floating lounge thing she was on.

 

[Synirr]

And I saw a commercial with a woman on a raft with two koi swimming below her. They had to be at least six feet long, they were longer than her or the floating lounge thing she was on.

While I won't say it's impossible, keep in mind that commericals often have these things called special effects

 

[andywg]

Slightly off topic...

I was wondering about whether the aquarium stunts all fish or not the other day.

Particuliarly Pim pictus. They grow up to 12" in the wild but only 6" in the aquarium.

Is this because they are stunted (i.e. there physically isn't the environment for them to grow larger) or because they are missing something - some event or microsubstance that triggers/extends growth so that they can grow to the larger sizes?

Andy

 

[freddyk]

You see all sorts of fish where they are supposed to reach 'blank' amount of inches/feet in the wild, but 'rarely grow this big in an aquarium'. Therefore, we stunt some fish all the time, it's just not as noticable.

Some fish stunt, many do not. Fish keep growing throughout their entire lives. The larger they get (all reletive to individual species), the slower they grow. It's the life span potential many fish never see, and in turn they never see their full growth potential.

 

[Undawada]

Ive always thought of the fish stunting as a myth. But it has a purpose, about not keeping fish in tanks too small for them. It could be true for all I know, but either way it serves as a deterrent for people just starting out.

It reminds me of the Goldfish slimecoat myth/fact. No proof has been given, but it keeps people starting out from keeping goldfish and tropicals together.

It's probably a myth created by fish keepers to stop new hobbyists from putting goldfish in bowls.

 

[Isis_Nebthet]

I have necropsied a three year old 12" koi before. It looked normal internally (aside from the color being off because it died of bacterial gill disease which causes palor from lack of oxygen).

 

[Tokis-Phoenix]

Ok, i would like to add some of my input as how posible it is for a fish's organs to keep on growing while the shell of the body does not, and how we may be looking at this from a completely wrong angle;
Tropical fish skin is nothing like human skin, tropical fish do not actually have the ability like we do to store long term fats like we or other mammals can mainly because living in a tropical enviroment you do not need fats to help keep you warm and if fish did they would often overheat and die before the fats could be consumed into the fish's body.
Without the need for long term fat storage their skin does not have to be and isn't very flexable/stretchable- in livebearers for example the only properly flexable part or skin that can stretch is the skin located towards the back or the female livebearers tummy where the fry grow- without it the fry wouldn't be able to grow at all in the mothers womb and would suffocate.
When a female livebearer has a huge load of fry in her, it is not uncommon for her to get dropsy in the week before she gives birth- this is not the kind of dropsy caused by desease or bad water quality, but simply the mothers skin being stretched to its limits and the result of this is the scales start to pinecone in an effect similar to dropsy in a last ditch attempt to create a little more stretch space for the mother fish's fry.
In a sense, this is simlar to a fish not having enough space for its organs and i wouldn't be suprised if a similar consequence happens to the female livebearer with too many fry in her in a fish that is stunted.

Taken into consideration that tropical fish skin, particually in male fish, is not very stretchable if at all, what happens when the fish's body is not allowed to grow while the organs continue to grow if they do at all?
Well the effects of this are many- the shortened lifespan is probably due to increasing poor circulation around the fish's body as room for circulation is cut off. The fish's organs would not explode as the poor circulation in the fish's body would kill it long before it reachs this stage. Your bodys growth like any other living creature is determined by genetics and cell growth, when cell growth grows faster in a partciular area of your body while normal in the parts around it you get a tumor- if a fishs body was stunted this would most likely disrupt cell growth and tumors would most likely be a very uncommon thing to happen in advanced cases of stunting.
Unless the fish has evolved its organs to stop growing when the body shell inner space is running out, there is no way it could say to its genes to stop growing its organs. If any fish have this ability yet, you would able to tell as their life spans would not be affected by stunting.

Stunted fish probably also suffer alot of health problems ascociated with obesity in humans; most fish's growth is stunted when the lack of tank space doesn't allow them to exercise properly, with a fish that isn't allowed to exercise properly it will become weak and circulation throughout its body will be poor- this could result in things like the fish equivilant of heart faliure/coronary heart desease. How to diagnose a heart attack in fish is yet unknown and probably doesn't show many if any symtoms on the outside appearance of the fish that we would be able to asociate with.

Soo...For the question, my answers due to my consideration of these facts are;
a. No, fish's organs would not "explode" it the fish was badly stunted as it would die long before it reached this stage due to other consequences of fish stunting.
b. If a particular life expectancy is not affected by stunting, it is ok for it to be stunted- if a fish's life expectancy is affected by stunting this is a large indicator that it cannot cope with stunting and it is bad for it and so any responsable fish keeper should not put the fish through this.
Fish that i know thats life expectancy is affected by stunting in particular are goldfish, plecs and angels- there are many more but these i totally know for sure.

 

[Tokis-Phoenix]

"bump"
No coments anyone?

 

[OohFeeshy]

I don't have any proof, no, but what I will say is that until is it definately proved otherwise, this should continue to be used as a deterrent. There might be no proof, but if it stops someone putting a common goldfish in a 1 gallon tank, I'm perfectly happy for people to think this way.

And I think to prove/disprove it, someone would actually have to do it. Compare the size/apparent health of a golfish in a 5 gallon compared to one in a 20. I say 5 because one is just too awful, the fish wouldn't be healthy enough to make notes on because of lack of oxygenation and poor filtration.

 

[Bignose]

But OohFeeshy, why should we decieve and bluntly lie to people? It may be a deterrant, but the facts -- the scientific proven facts -- should be enough if the person is going to be deterred at all. Also, some stunting experimentation has been carried out, I cited the sources in my first post.

Tokis, why would the fish's genes devote resources to only growing the organs without a corresponding devotion of resources to growing the skeleton and the outer skin as well?

Good discussion so far, I am still hoping someone may have proof of this -- otherwise I would sure like to see it put to bed for good.