[Ranchugirl]

While being on the koi/goldfish show a couple of weeks ago, I listened in on an interesting discussion about the importance of waterchanges, and this is what I learned....
Participants were a half a dozen experienced koi keepers with a few expensive koi in their collection (except me, of course :lol: ), and they were trying to explain a newbie why it is so important to change the water frequently...
Its not only to reduce the amount of waste and nitrates in the water. More importantly it is to get something out of the tank that would hinder the growth of the fish....A fish expells a growth inhibitor while breathing, and that growth inhibitor remains in the tank/pond, and with enough accumulation due to lack of water changes it hinders the fish in his growth, meaning the fish will stop growing. With water changes the inhibitor will be deluted and reduced in the fishies environment, and the fish can continue to grow.
As an example one koi keeper told us about two specific koi ponds in his neighborhood. Both ponds had about the same volume of water, with more or less the same amount and sizes koi in there, and since they were in the same neighborhood, the same amount of life foods available to them like mosquito larvae and daphnia.
One pond had a regular filter system with it, the ones we would have in a smaller version on our tanks - mechanical and biological filtration. Water changes were done on a regular basis once a week, always the same amount of water.
The other pond also had a filter connected, but it had a continuous system where the water would be drawn from a well, conditioned and pumped into the pond, while the overflow constantly was putting water back into the environment. This pond had constantly fresh water coming for the koi.
Both koi keepers fed their fish the same food (HiFeng growth food for koi), but the koi in the pond with the constant supply of fresh water had much bigger koi in there in a much shorter period of time. The growth inhibitor in that pond is constantly being swept out and away from the fish.
NOw, you might say, these owners bought fish from different sources and thats one explanation on the different growth rate. But they took it further, they both bought a dozen goldfish from a local koi importer, from the same breeder in China, and each of the two put his fish into a separate pond on their properties. Same thing happened again - the goldfish in the pond with the constant fresh water grew bigger faster than the ones in the pond with the weekly water changes.

This does not mean we should perform daily water changes in our tanks, but it means one thing - keep up the routine water changes, don't be lax in it, do a little extra for your fish, and one more thing..... Food and more feedings are not the only thing that you need to know about if you wonna have big fish. The growth rate of fish is a complex story, and involves a few other things than just putting exsessive amounts of food into our tanks and hope for the best....

So, lets roll out those buckets and containers, and the calendar, so we don't miss any of those very important water changes! :happydance

[chellekins27]

wow!! that was a very interesting read ranchu! i learn something new everyday! it's especially interesting to me since i have a research class this semester and that is the perfect example of a controlled experiment! definite cause and effect there! makes me want to pull out the buckets right now, except that i just cleaned all my tanks yesterday! :D

thank you for sharing!!!

:hi

[gchen]

Well, how do we know that the inhibition of growth is not due to differences in nitrate levels? Did these guys confirm that nitrate levels were similar between ponds?

[gchen]

Here's an interesting article at Goldfish connection:

http://www.goldfishc...d=67&parentId=8

I had done some worst case calculations assuming that all food eventually becomes nitrates and similar conclusions that I couldn't keep nitrates down without changing the water everyday! That's why I'm experimenting with reducing food intake.

[toothless]

i read about this theory a while back and i like the idea. your story seems to be a perfect example. it just leaves a few "holes" open as far as other growth enhancing variables that may have been different between the two ponds. dont get me wrong, i do like the idea. :lol: was there any info on the differences in water params? there is similar theory involving plants and structural growth. the theory is that there is a growth inhibitor (sp?) in plants that are in greater numbers at certain heighths along the main stems that allow certain amounts of growth at certain points. (sorry if that wasnt clear) i too like this theory and have seen it at work among the plants that ive grown. :D

[HappyGoldfish]

And if the fish are cramped and hormonally stunted when young, they won't ever catch up. Another good reason not to crowd your tanks!

Great post, Ranchu. :)

[slipperylittlesucker]

very interesting
did you manage to get the name of the inhibiting substance?
if you said it was expelled while the fish were breathing
then it might be carbon dioxide or ammonia
nitrates is mainly derived from their faeces

[bruce]

:huh: say the guy thatdidn't have the fresh over turnover but started to would his fish start growth agin or is perenate excuse my spelling

[Ranchugirl]

Well, about other things in both their ponds - neither one of them had plants.... Both had UV sterilizers. I don't know if both of the ponds were in shade or sun.
SLS, I didn't catch any name of the inhibitor, they might have mentioned it, but I am not too good with chemial stuff, so I might have missed that one... :)

[JessicaandMarshall]

Well that explains why several of my fish grew 2" plus in less than two months....I was doing daily water changes in that time frame :rofl as well as high quality food, and lots of growing room :lol

I guess I should step up my water changes again. Maybe 2 or three times a week? :D

Very interesting post Ranchugirl.

Jessica

[toothless]

i wonder if the (theoretical) growth inhibitor from one goldie affects other goldies? i would imagine that it does. after all, all goldfish are the same species. ive been searching the net for more info on this and other theories. no luck yet. :)

[gorgonitz]

you are spot on about the growth inhitors. I have been keeping discus and this growth inhibitor thingy is really an issue. Lets get our hoses and buckets ready.

[fishfelice]

Wow! thanks for the informative post! That theory makes sense, I've always wondered what could possibly be the reason fish stopped growing in cramped conditions- I mean how could their body know to quit growing? If it is because they always release a growth inhibitor, than the smaller the area the more inhibitor they are living in and the less they grow, if they are in a large area of water, then they are not as engulfed in the inhibitor (it disperses) and they grow larger.

[gchen]

Here's an interesting link that also supports the theory that water quality may be the limiting factor to fish growth. However, in this case, the mystery inhibitor may just be nitrates.

http://kokosgoldfish...?showtopic=8064

[HappyGoldfish]

The "growth inhibitor" Ranchu is talking about is, I assume, the buildup of hormones in the water. I say "assume" of course, because I wasn't present when the conversation took place, so I can't say for certain what they were talking about, but in my mind it's the only thing that fits. Fish kept crowded for extended amounts of time at a young age will artificially mature and will stop growing. Once this happens, you can't turn back the clock. If a fish is not growing due to some other factor (stress from water conditions, disease, poor nutrition, etc.) and then the fish's conditions are improved, it will likely still grow out to near where it "should" be (genetically), but a fish that has been hormonally stunted at a early age is never going to reach anywhere near its genetic growth potential and may stop growing altogether.

[Lovely_Goldfish]

wow so my weekly 1/3 water changes isnt enough? shirari was right, no wonder her kois grew an inch a month! I am noticing my koi growing faster since I feed em pelets twice a day with weekly water changes. I guess in nature fish cant outgrow their surroundings but constant water changes will fool nature and the fish thinks its in a large lake

[slipperylittlesucker]

this is a revelation
it goes a long way to explaining why fish grow much faster
in ponds
i always knew that water chemistry was just as important to
a fish's growth as with food and space
and this gives a good case
from now on, im doing more water changes :)

[scousersharon30]

WOW, thanks for the heads up on that one Andrea. It was really interesting and I will definately keep up with the water changes :)

[Raivynn]

Hate to be miss know-it-all, but I've actually heard this before. YEARS ago. I had said something about a koi that is 10" long and around, oh, 4-5 years old. I was told a koi that old should be pushing at least two feet. He asked where I was keeping him, and when I told him a 29g tank, I thought I told him I'd walked on the moon barefoot or something. I ended up buying a new tank a few months later. He's put on about an inch or so since the move to a 46g back in April of '03, so I know he puts out quite a bit of the hormone that can stunt fish's growth. Interesting point: My smaller koi still continue to grow at a faster rate than he does. I change my water once or twice a week. Fish load is going to be significantly reduced when pond season opens up. I hate to part with my koi, but I will keep 2 or 3 of them and sell the rest.

It's a hormone [can't remember the name of it] that causes the stunted growth. It's Mother Nature's way of ensuring a fish doesn't outgrow his natural environment. Kinda makes sense - a small fish in a small pond will fare better than a large fish in a small pond. So, Mom Nature designed something to prevent it from happening in a natural environment. We interrupt this when keeping fish in our tanks - by our water changes. It's not so much we fool them into thinking they're in a large lake or something of that nature, it's more like just taking out "dirtied" water and replacing it with clean stuff. [Well, that could be considered making the fish's system believe it's in a large lake....oh well. ^_^]

So....water changes, water changes, water changes.

Rai

[HappyGoldfish]

Quote

Hate to be miss know-it-all, but I've actually heard this before. YEARS ago.

This isn't new information, it's just not something most fishkeepers have happened to hear about. It's not crucial information for people to know to keep their fish healthy, so it isn't talked about as often as core issues of the hobby.

If your tanks aren't overstocked and you do regular water changes, you don't have to worry about your fish being hormonally stunted, so no reason for us all to start hooking up the plumbing for a continual drip/drain system (though that would be nice - hmm...). ;)