# Water changes and fish growth



## danielratti (Feb 17, 2008)

Ok so I've seen a lot of posts online saying that if you were to feed more and do more frequent water changes it will speed up the growth process of the fish. How much of this is a myth. I've been breeding fish for a couple years now and weekly water changes are what I do on my tanks and the fish seem to be doing fine with growth.


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## DJRansome (Oct 29, 2005)

I have not seen feeding more to be a plus. And the frequent water changes I've seen in connection with speeding *fry *growth...not juvenile or adult.

In your experience, you do not see faster growth if you have two fry tanks and do daily changes to one and weekly changes to the other?


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## danielratti (Feb 17, 2008)

*** never done daily changes since sometimes in my fry tanks I will put some of my smaller juvenile fish in there to grow some before going into my main tank. Right now in my fry tank I have what was sold to me as a male sulphur head peacock and he is close to 2 inches a little bigger actually but the fry have been in that tank for about one and a half months and are about 1.5 inches with weekly water changes. I mean I could do daily and see if that changes anything I only take out like 6 gallons a water changes since I over filter big time.


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## BillD (May 17, 2005)

There really is no such thing as "over filtering". Once your ammonia and nitrite numbers are at 0, you can't go any lower by increasing filtration. As far as clean water being essential to rapid growth, in my experience, that is absolutely true. ditto with increased feeding accompanied by enough water changes. Research has shown that if a fish's diet is reduced by 70% from optimum, the fish will still grow, albeit slowly. So, from that you can surmise that feeding as much as the fish can (readily) consume, will result in rapid growth. This is easily demonstrated with angel fry, who will grow much more quickly fed 5 or 6 times daily, as opposed to 3 times daily. Juvenile fish will also grow more quickly, if they have lots of food available. This I have seen for myself when keeping live food in front of the fish, 24/7. most fish will stop eating when stuffed, until they have room for more. There are some exceptions. My experience with bettas indicate they will continue to eat live daphnia, until none are left, regardless of how many you give them. They just have huge stools, that pass through them quickly. the high percentage of bulk that daphnia have relative to nutrition, allow for this to work.


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## cantrell00 (Oct 30, 2010)

I had mine on a continuous drip & didn't see any growth rate improvements... IME, the most important thing with raising fry is water volume.. The larger the body of water, the faster they will grow, assuming everything else is equal. Adequate filtration and a hi-protein food.


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## BillD (May 17, 2005)

cantrell00 said:


> I had mine on a continuous drip & didn't see any growth rate improvements... IME, the most important thing with raising fry is water volume.. The larger the body of water, the faster they will grow, assuming everything else is equal. Adequate filtration and a hi-protein food.


Large water volume is simulated by large frequent changes, but, of course, a small number of fish in a large tank will have cleaner water with fewer changes. How much water was changed daily with the drip? I did 60% to 70% daily with the angels, during grow out.


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## countryboy814 (Feb 19, 2012)

Isn't overfeeding associated with bloat?


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## danielratti (Feb 17, 2008)

Right. This is why I questioned this logic. I was also told that too many water changes will take out your good bacteria...


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## countryboy814 (Feb 19, 2012)

danielratti said:


> Right. This is why I questioned this logic. I was also told that too many water changes will take out your good bacteria...


Good bacteria hangs in the substrate and filters. Water changes take out nitrates and amonia causing waste.


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## cantrell00 (Oct 30, 2010)

BillD said:


> cantrell00 said:
> 
> 
> 
> ...


I don't think a continuous drip simulates an increase in water volume at all. At least in my limited tests, I never saw an increase in growth rates. I think the more space they have, the faster they grow. Obviously, the larger the holding area, the more gallons of water are required.

The only thing I see as an advantage with a continuous drip is that the nitrates stay lower more consistently & the convenience of not having to do the water changes yourself. The impact on growth was immeasurable IME.

I guess you could make the argument that the best of both world's would be a very large body of water AND a continuous drip.


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## 24Tropheus (Jun 21, 2006)

I tried lots of feeds (4 times a day) and lots of waterchanges (every two days) growing on comps in a 29g.
Found the ones just fed twice a day with just weekly waterchanges in a 180g grew faster.
Same sort of things with Mbuna though the growth rate for those far far faster in both set ups.
Im with the big water volume guys.


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## DJRansome (Oct 29, 2005)

Overfeeding IS associated with bloat, but in many cases this is incorrect, even with adults. IMO bloat is much more closely associated with stress but feeding the wrong foods can be a stress contributor.

However fry rarely get bloat and can handle a higher protein food as well.


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## countryboy814 (Feb 19, 2012)

I'm sure I read that bloat was caused by food not passing through the intestine. The always present parasites feed on the food in the digestive tract causing bloat. Normaly the waste is passed right through not giving the organisms time to eat much.


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## GTZ (Apr 21, 2010)

countryboy814 said:


> I'm sure I read that bloat was caused by food not passing through the intestine. The always present parasites feed on the food in the digestive tract causing bloat. Normaly the waste is passed right through not giving the organisms time to eat much.


Not quite. The flagellates present in the digestive system become over abundant due to a lowered immune system, usually brought on by stress. Infection is another common occurrence due to the lowered immune system.


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## countryboy814 (Feb 19, 2012)

GTZ said:


> countryboy814 said:
> 
> 
> > I'm sure I read that bloat was caused by food not passing through the intestine. The always present parasites feed on the food in the digestive tract causing bloat. Normaly the waste is passed right through not giving the organisms time to eat much.
> ...


Is it the over abundant flagellates that cause the intestinal blockage?


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## GTZ (Apr 21, 2010)

As well as mucus, yes. There are other theories suggesting that the main cause is bacterial and not parasitic.


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## lucid_eye (Apr 12, 2009)

I would have to look up my research from way back when I got interested in the subject of growth rate, but from what I remember is the following. The rate at which fish grow and mate can be impaired by the level of pheromones in the water, the higher this level is the greater the population density of the tank. Therefore fish evolved at some point to keep their population in balance with available resources (food, oxygen, etc.). If this pheromone level is high it would stunt their growth and make the adults less inclined to mate. This is also why you often see breeding occur shortly after a water change or when the weather starts acting up outside. So water changes will benefit growth rate but only to a certain extent. If you change the 80% of the water every day if probably wont be any better than changing 50 every other day. It really depends on how quickly the pheromones are building up.


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## cantrell00 (Oct 30, 2010)

lucid_eye said:


> I would have to look up my research from way back when I got interested in the subject of growth rate, but from what I remember is the following. The rate at which fish grow and mate can be impaired by the level of pheromones in the water, the higher this level is the greater the population density of the tank. Therefore fish evolved at some point to keep their population in balance with available resources (food, oxygen, etc.). If this pheromone level is high it would stunt their growth and make the adults less inclined to mate. This is also why you often see breeding occur shortly after a water change or when the weather starts acting up outside. So water changes will benefit growth rate but only to a certain extent. If you change the 80% of the water every day if probably wont be any better than changing 50 every other day. It really depends on how quickly the pheromones are building up.


This is great information and would really explain why there were/are discrepencies in ppl's experiences on this subject.

I would imagine that few fish in a large body of water provide a greater margin of error for if & when these pheremones, genetic/DNA cues etc. kick in & demand that everything slow down to allow time for things to strike a balance again... It makes a lot of sense when you review it with this information in mind..

Thanks!


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## 24Tropheus (Jun 21, 2006)

Do all individuals produce as much pheremones as others? Why can you can grow an Oscar Pair to 12"+ in a tiny tank? Its also kind of odd if large lake fish bother putting energy into producing stuff that would be dilluted to pretty much nothing by the large quantities of water they evolved in. Small pond fish yep it could be of an advantage to put energy into reducing the growth rate of others this way.
My guess is research from one species of cichlid is not transferable to another.
I would guess the reduction in growth is more due to physical bullying or intimidation and the general lack of health crowded fish suffer from (if you do not remove all waiste products by regular water changes) but again prob varies from species to species.

Not at all convinced by any pheromone argument/theory. :wink:

All the best James


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## cantrell00 (Oct 30, 2010)

24Tropheus said:


> Do all individuals produce as much pheremones as others? Why can you can grow an Oscar Pair to 12"+ in a tiny tank? Its also kind of odd if large lake fish bother putting energy into producing stuff that would be dilluted to pretty much nothing by the large quantities of water they evolved in. Small pond fish yep it could be of an advantage to put energy into reducing the growth rate of others this way.
> My guess is research from one species of cichlid is not transferable to another.
> I would guess the reduction in growth is more due to physical bullying or intimidation and the general lack of health crowded fish suffer from (if you do not remove all waiste products by regular water changes) but again prob varies from species to species.
> 
> ...


When put in this context, I would have to agree... Unless you assumed that this pheremone would only be present in the event of extreme enviromental changes.. The problem with that argument is just as you have mentioned.. How do you reconcile that with multiple cichlid species?

So, back to where I started & this is my observation without knowing anything else. My fish seemed to grow at a more accelerated rate in a large volume & area of water. Can't explain why. The end. :thumb:


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## lucid_eye (Apr 12, 2009)

I do not take credit for any of these articles the site I stole the info from is below the articles

All living things, by definition, engage in biological, read that as bio-chemical/physical reactions transforming some materials, utilizing energy and producing "waste" and growth products and so-called by-products. The various chemicals changed and passed outside particular species may be classified in the following way:

1) Having no specific/known effect(s) on the secreting species or others.

2) Having such effects:

A) On the species itself (pheromones)

B) On other species (allomones)

What is this Stuff, Anyway?

Many exocrine (versus endocrine) substances have been isolated/identified to have G.I.S. and/or G.S.S. effects. Ammonia-derived metabolites, amino acids and combinations of A.A.s, and most notably short chain fatty acids, have been demonstrated to accelerate/retard the individual growth and behaviors of many groups of fishes.

Most "advanced" (old and wrinkled?) aquariologists know the practical whys and wherefores (consequences) of these substances. Some highlights:

1) Everything else being equal (that is, no food, gas, physical space, filtration, lighting, temperament, other limitations) some same-species fish substances:

A) restrict spawn sizes, differential growth rates of individuals and groups of individuals, further:

B) limiting their subsequent reproductive viability, and even:

C) the smaller (runt) individuals survival rate (demise).

2) Mixing species often lessens the pheromonal stunting effects of a single species alone.

3) Boiling the water, leaving it to age (for weeks), dissipates the responsible compounds.

4) Removal of some or all of the larger members of a spawn or population spurs the growth/development of the next larger individual(s).

5) Some of these materials have beneficial and antagonistic impacts. That is, using "old water" has shown healing and growth-positive actuation compared with absolutely fresh (i.e. no-same-species-chemical secretions) water

6) That frequent massive to partial water changes and effective chemical filtration lessen these effects.

Why? Tell Me Why?:

Towards what possible ends would/should organisms produce such self-limiting secretions/excretions. Several reasons come to mind: 1) To preclude over-crowding and loss of the whole population due to food, oxygen/carbon dioxide limitations, other controlling factors, in the otherwise absence of other species competition or predatory pressures. And I'll leave it up to you to decide whether this one should have been mentioned first, 2) the ole Chucky Darwin Natural Selection (long may it wave?). By having the most humongous citizens beat out the less-humongous as a gauge of "fitness", may enhance the overal survivability of the species.

Where's this Stuff Come From?:

Principally growth stimulating/retarding substances have been found, and presumably are released by way of, body slime, excretory discharges from the anus and gills, and traumatic damage to the organism in general. This last category will explore in our next visit as Schreckstoffes: Alarm Substances of Fishes.
http://www.wetwebmedia.com/fwsubwebinde ... tChems.htm

Somatostatin is classified as an inhibitory hormone,[1] whose actions are spread to different parts of the body:
Anterior pituitary

In the anterior pituitary gland, the effects of somatostatin are:

Inhibit the release of growth hormone (GH)[5] (thus opposing the effects of Growth Hormone-Releasing Hormone (GHRH))
Inhibit the release of thyroid-stimulating hormone (TSH)[6]
http://en.wikipedia.org/wiki/Somatostat ... tostatin-4

In the present study the effects of somatostatin on serum growth hormone (GH) levels in the goldfish, Carassius auratus, were investigated. A single intraperitoneal injection of either 0.1 or 1.0 μg somatostatin/g body wt caused a significant decrease in serum GH levels at 1 h postinjection compared to vehicle-injected controls. Two intraperitoneal injections of somatostatin (1.0 μg/g body wt), given 12 hr apart, caused a significant decrease in serum GH levels, compared to both presample and vehicle-injected control groups at 1.5 and 6 hr following the second injection. In fish given two injections of somatostatin, a post inhibitory rebound in serum GH levels occurred by 24 hr following the second injection. Thyrotropin-releasing hormone (1 μg/g body wt), given as a control peptide, caused a significant increase in serum GH levels at 24 hr, but no significant changes were found at 1.5 or 6 hr following the second of two intraperitoneal injections given 12 hr apart. The increases in serum GH at 24 hr may be due to stress. The results demonstrate that somatostatin causes a transient decrease in blood GH levels in goldfish.
http://www.wetwebmedia.com/fwsubwebinde ... tChems.htm


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## lucid_eye (Apr 12, 2009)

24Tropheus said:


> Do all individuals produce as much pheremones as others? Why can you can grow an Oscar Pair to 12"+ in a tiny tank? Its also kind of odd if large lake fish bother putting energy into producing stuff that would be dilluted to pretty much nothing by the large quantities of water they evolved in. Small pond fish yep it could be of an advantage to put energy into reducing the growth rate of others this way.
> My guess is research from one species of cichlid is not transferable to another.
> I would guess the reduction in growth is more due to physical bullying or intimidation and the general lack of health crowded fish suffer from (if you do not remove all waiste products by regular water changes) but again prob varies from species to species.
> 
> ...


I am by no means an expert, but became interested in the subject a few years back and found many studies that backed the idea. I am sure that just like everything else two fish from the same spawn could produce drastically different quantities of the chemicals. And I would theorize that the "dirtier" fish, such as goldfish or carp, excrete more than other species. As to why you can have an Oscar grow to 12" in a small tank? I have seen this happen my self so it does happen, but that is irrelevant. The fish is still alive and functions normally however the growth is inhibited (not halted). Given that the diet, genes, etc, of two fish were identical do you honestly believe that an oscar will grow just as quickly in a 10 gallon tank as the other in a swimming pool by itself?

"Its also kind of odd if large lake fish bother putting energy into producing stuff that would be dilluted to pretty much nothing by the large quantities of water they evolved in" Similar to the way that it is odd humans put energy into producing similar chemicals that come out of our armpits and quickly get diluted by the vast amount of air around us. This is not a conscious act, but a mutation that improved the odds an organism would continue to exist.

Small pond fish yep it could be of an advantage to put energy into reducing the growth rate of others
Again not a conscious decision, and its not about reducing the growth of others, it is about regulation of the entire population, they are stunting their own growth at the same time. Hypothetical oddball metaphor here: On planet Zork people live in caves, in these cares are many types of foods. However, there are Bean berries in these caves and if you eat them everyone within 10 feet of you will eat everything they see for 5 days, including yourself. These people could possibly wipe out their food supply if they continue eating the berries. Unless one of them was born with a mutation that caused them to become immune to the berries. This mutation would likely keep the species alive. Likewise without this mutation many species of fish would not exist today.


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## 24Tropheus (Jun 21, 2006)

24Tropheus said:


> Not at all convinced by any pheromone argument/theory. :wink:
> 
> All the best James


Always interesed by the quality of answers when I play devels advocate. Note the :wink:

Some interesting points come up. The difference between pheremones and inhibitory hormones and allomones as well as their antagonistic impacts.
Seriously if anyones armpits give off stuff strong enough to retard growth in others, seek professional help. :wink: 
On (another :wink serious note these processes may no longer be of importance to fish in the wild but a hang over from when they evolved in small bodies of water. And yep if still effective in the wild just imagine their impact in small tanks without regular waterchanges!
Kind of explains why some species can be larger as wild caught than we can easily achieve in tanks?

All the best James


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## lucid_eye (Apr 12, 2009)

This thread re-peaked my interest in the subject, and I began to do more "research". Unfortunately I found conflicting information and studies that showed different results in separate species of fish. Then there were the articles that were in babble that I couldn't understand without a couple more years of biology. So the experts may not quite understand the exact function and effects of these chemicals any better than we do. So asserting one idea another as anything more than theory at this point may be ridiculous. The one piece of information that I did see over and over was that there is a definite link between the production of growth hormone and the level of these pheromones in the fish. FWIW


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## 13razorbackfan (Sep 28, 2011)

lucid_eye said:


> This thread re-peaked my interest in the subject, and I began to do more "research". Unfortunately I found conflicting information and studies that showed different results in separate species of fish. Then there were the articles that were in babble that I couldn't understand without a couple more years of biology. So the experts may not quite understand the exact function and effects of these chemicals any better than we do. So asserting one idea another as anything more than theory at this point may be ridiculous. The one piece of information that I did see over and over was that there is a definite link between the production of growth hormone and the level of these pheromones in the fish. FWIW


I remember reading this as well but also remember that i read somewhere that it reduces as the fish age. Anybody know if this is true?


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