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 ), 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!

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!

thank you for sharing!!!

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?

Here's an interesting article at Goldfish connection:

http://www.goldfishconnection.com/articles...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.

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. 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.

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.

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

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

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...

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 as well as high quality food, and lots of growing room

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

Very interesting post Ranchugirl.

Jessica

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.

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.

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.

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.com/forum/index.php?s...?showtopic=8064

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.

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

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

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

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

wow, you're really not kidding about the water changes! my readings from the test lab have been outstanding since i've been changing the water more and the fish's fins are much more healthy! the fin rot actually cleared itself up without medication since i've been changing the water. i love it
i am dying for my 100th post so that i can send you guys some pictures, i have GREAT ones!!

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...).

WOW! That was interesting! Guess u learn something everyday! (even tho today i didnt learn a thing-like usual- at skool) lol

Bubbles!

Rai, I figured its not new about the growth inhibitors, but I figured with so much doubting and debating going on on the board lately about trying to get away with keeping more than 1 fish in 10 or 20 gl of water, and sometimes I see waterchanges being done once or twice a month, I thought, its the right time to bring it up!

How many fish can you keep in a 90 gallon aquarium?

The general rule is 10 gl per fish, but it depends on the breed of the fish. Its really only a bare minimum, when the fish are small. Bigger fish I would give 15-20 gl per fish, and something like a comet or a shubunkin, who grows really big really fast, needs around 20-30 gl per fish. What kind of fish do you have, Martinez?

I have what you would call "feeder fish," a black moor, and a betta

Well, the black moor would fall into the 10 gl/fish rule, while the common or comet (I don't know who came up with the rather cruel name of feeder fish) is one of the breeds that grows bigger and needs a bit more space.
As for the betta, he is fine with anything as long as its not a tiny cup with no filtration or water change. I have mine in divided 10 gl tanks, and house 4 males and 3 females together in that tank, the males put each in their separate compartments, with a spongefilter....

what exactly are sponge filters? i know bettas don't like current...right>?

Sponge filters are rather simple, they are sponges and come in different shapes, depending on how big your tank is. They are connected to an airpump via airline tubing, and the air gets pressed thorugh the tubing into the sponge, and comes out as air bubbles. That technique draws any waste towards and under the sponge, and the bacteria culture that develops over time in the sponge takes care of the waste. Its purely biological filtration, but it keeps the waste pretty much under the sponge, so its easy cleanup when vaccumming the tank bottom...

I was always curious about those. thanks for explaining that ranchu

Aloha Andrea,

I know I'm a little behind getting on this band wagon, but that was a awsome post. Talk about making the big picture click.

Clear water

Great write up Ranchu!! I am still learning, and have had some "tank problems" with keeping the water chemistry right. I have been doing a lot of water changes! I will continue to keep the water changing as a high priority, even when the tank finally stabilizes! I want my little guys to be "big guys" soon!!

wow, I tried this and I can see a huge difference in just 2 weeks!!! I have a 20 gallon tank with 2 black moores and a shubunkin...all three have almost doubled in size

Wow!! That is good! I have been doing 30% water changes, twice a day for the last week and change! This is really due to a high NITRITE problem, but.....my wife was just commenting on how much bigger the Oranda seems to be! And his head growth (wen) as well! The Lionhead has grown noticibly as well, but not as much as the Oranda! I think there may be something ot htis water changing!!!

Wow thats interesting ranchu ... thanks for sharing

How long does it take for a goldfish to get hormonally stunted? I have had two small (3-4") fancy goldfish in a 10 gallon tank (consistantly ammonia 0 nitrites 0)for 6 months. Theve both grown 25% or so since I've had them, and show no signs of stress. I've been giving them regular water changes once a week or more. I'm moving them soon to a 55 gallon tank and hope I haven't stunted the little guys...

Wow.... I reeaallllllyy should change my fish's water -- in the pond -- more, then... after this I changed 15% of it, and it looked pretty chaotic...but as soon as it calms down, perhaps my fish will be happier?

TEN TO ONE SOMEONE WILL SAY I WANT LITTLE FISH OR I DO'T WANT TO BUY A BIGGER TANK SOOOOOO... I DON'T NEED TO DO WATER CHANGES :goldfish

I am so glad I stumbled on this post. I was just wondering if I should continue with my 50% water changes. I have very low ph out of the tap so have been working and experiementing to getting it up so have been doing big water changes. I don't mind and it looks like it is great for my babies (Goldies, lol)

Thanks again!

alrit, i just change 50% of my water.

usually i change the water once there is a rise in the ammonia and nitrite levels. but after reading this article by ranchugirl, i think i will have to schedule more water changes now.

thanks!

This is very interesting! Thanks for sharing ranchugirl! I don't think I need to water changes yet. My fish are still in the pond and I just put 5 snails in the tank today. (their slough snails not even the length of my fingernail) But I'll have to get a calendar to remember the water changes!!

Robyn

I have kept pond fish for almost 7 years (comets, fantails and a few inbetweens). During the first 5 years I did regular water changes - the fish grew.

Over the past 2 years my area in Australia has been hit with Emergency water restrictions - no water changes (OK, so I cheated and did a water change every 8 months or so).

The fish continued to grow, rate unchanged.

They have also remaind remarkably healthy,probably because the pond has a great deal of rock in it which would harbour the bacteria needed to keep the water healthy.

So, if this theory on hormone levels actually holds any water (so sorry, I couldn't resist the pun), why did my fish continue to grow with water changes only every 8 months or so?

In your case my guess would be that fresh water naturally has entered the pond when it was raining.
Pond fish do a lot better with not all that constant water change than tankfish would do, simply because most ponds have a much greater water volume compared to a tank. A 2000 gl pond would take a much longer time to accumulate those growth inhibitors than a 150 gl tank would need. MOst ponds are not overstocked, rather understocked, with fish. Less fish + greater volume of water = more time without water change.....

Very little rain (in fact we went 8 months without a single drop) - worst drought in 100 years - thus the emergency water restrictions. I've had to constantly top up the pond with tap water (adding water ager etc).

It's a lovely theory, but I'm just not sure it works. These fish have done brilliantly in literally stagmant water for 2 years. Fish that were fry 2 years ago are now 5-6 inches long. (And the pond is fairly heavily stocked - 500 inches of fish for 1500 litres - don't know how to convert that to gallons, sorry!)

So is there such a thing as too many water changes?

I have been doing 20% water changes every day for about a month, just because it's easy with a python, and the fish seem to enjoy it!

I must say they are growing leaps and bounds (I have 2 shubunkins, two sarasa comets and one common in a 55 gallon). Even with the water changes, I have to be careful not to overfeed. They are such pigs!!

KYskipjack

So I spose this is where the "fish grow 2 the size of there tank" thing came from cause a fish in a small tank with out water changes will not grow... but in a larger tank it will take longer 4 this 2 happen so it will grow a bit...

Well, I got Blackie a 20g to himself about 4 weeks ago (with a couple of wee pearlscales for company). I could swear he has grown heaps in that short period of time, so much so that I had to put him into the 40g because he was looking 'cramped' for space. He is now my 2nd biggest fish, a month or so ago he was my 3rd biggest.

Could this growth spurt be related to the relatively low nitrAtes and growth hormone in a freshly cycled tank?

Even before this growth spurt he has grown fairly quickly and doubled his size in about 9mths. Now I think he'll eventually end up in the bathtub!

nb. He is currently about 3" in body length without tail.

A goldfish in the bath tub, now there goes an idea! I'll remember that if I ever run out of space otherwise!

It could very well be, Annette, that that's the reason. I have seen quite a few fish that had a sudden growth spurt right after they moved into a bigger tank...

so with all those water changes...how do you keep your tank from recycling?????

Forgive my question... I'm still trying to get this stuff down pat