empirical evidience that daily massive water changes are best for discus?

[xyyz]

i hear lots of advice about how at least 30% of the water in a discus talk should be changed. and how the tank outta' be a bare bottom tank etc.

my question is this: is this all urban legend? has anyone ever conducted a controlled experiment that's been published and reviewed by peers? i'm not talking about hobbyists - no matter how many years they have in the hobby, but actual university educated ichthyologists?

i'm sure people can claim that they've run through trial and error, and that daily water changes are the best (some even say dump out all the water 'till the discus can barely stay vertical) but i doubt they've had a regulated environment with a control group.

i don't understand the reasoning behind the daily water changes anyways. if you siphon away food and other detritus regularly, how exactly is two day old or even three day old water unclean?

 

[runninwoof]

this is what i think, although im no discus keeper/breeder

the more partial water changes you do, the bigger and faster a fish will grow.
discus are also the most prized freshwater fish, and being that, i would imagine they desire pristine water conditions, and while i believe that 2 day old water wouldnt nessisarly hurt them. i think that the daily water changes help relieve what small stress and toxins they are feeling.
also if i were keeping discus, i would want them to have the best water quality i could imagine. maybe even two water changes a day. they are really beautiful fish and deserve the best

 

[dmoney87]

I would have to agree with runninwoof.. Its a matter of principle rather than a mater of .. science?? if thats what you were going for. I dont think that two day old water will adversely effect discus and the bare bottoms are usually meant for when breeding.. but whats the big deal about changing the water .. nature does it with rain we do it with a python.. just so happans were a little more technologically advanced than nature.. thus having the capabilities of keeping the water clean more often than not.. and I dont see how you can refute the main point that not changing the water in aquariums can have any positive effects.. they are after all the most expensive freshwater fish to keep... and we all protect our investments.

-davE

 

[CaptainAhab]

Water changes in part remove nitrates which have been proven to be harmful to fish. Also if you siphon away food and other detritus regularly and replace that water then you have in essence done a PWC

In the end be it anecdotal, scientific or urban legend you'd have a hard time finding ANY marine biologist, biologist of any specialty that would disagree regarding the value of the PWC in the home aquarium.

Bare bottom just makes it easier to clean all of the food and other detritus thus keeping the nitrate rise slowed due to getting that stuff out before it can decay. However nitrates will still be created by the biological process and short of plants and some other outside filtration choices PWC's are the easiest way to keep them down.

Now you can google and get plenty of examples of people who have done/tried self contain ecosystems. Before you take that as gospel make sure you note the cost and how long they have been running unattended.

Science experiments are fine but some of us have alot of money invested in livestock and tanks that have been around for years.

In the end PWC's are the great cost/benefit action you can do for your tank.

 

[Zagz]

If you keep a bare bottom tank for discus which many breeders do, then daily water changes are more essential as there isn't as much for beneficial bacteria to attach to.

When discus are juvies, it is easier to keep them in bare bottom tanks and do daily water changes.

I personally keep a 75 gal heavily planted discus tank which requires only weekly water changes as the plants do suck up the nitrates. I actually have to dose nitrates to keep some nitrate in the water for the plants. I aim for 5-10ppm nitrate. I do 50% water changes every week, some weeks I may do an additional 25% if the fish have been eating more and producing more waste.

The discus are more mature and the tank was well cycled before any discus were added.

 

[bs6749]

If you keep a bare bottom tank for discus which many breeders do, then daily water changes are more essential as there isn't as much for beneficial bacteria to attach to.

I have do disagree somewhat here. It's true that having a bare bottom tank provides less surface for the nitrifying bacteria to grow, but breeders and hobbyists make up for this by adding a 2nd or 3rd sponge filter (most commonly used in a growout tank). Being bare bottom allows the hobbyist or breeder to notice excatly how much waste is polluting the tank that sand and gravel could otherwise hide, not to mention make it more difficult to remove.

The goal of changing out the water isn't just to remove nitrates. Many discus keepers will often times keep potted plants in bare bottom tanks to remove nitrates from the water when growing out juvies. One of the most important things to remove from the water besides the excrement is the hormones that the growing fish secrete. Fish secrete hormones into the water and if they build up to a high enough level they will prevent the fish from growing i.e. stunt the fish. This is exactly why it is recommended to change more water more frequently for sub-adult discus. Adult discus don't have much growing to do and they won't be stunted from a buildup of these hormones. The water of an adult discus tank therefore needs to be changed less often, mainly to reduce the nitrates.

Some breeders will change out 100% of the water 3-4 times per day and they are also feeding at least a dozen times per day. The results can't be argued with however. Phenomenal growth rates can be seen with ample amounts of fresh water and by filling their bellies with food.

 

[xyyz]

In the end be it anecdotal, scientific or urban legend you'd have a hard time finding ANY marine biologist, biologist of any specialty that would disagree regarding the value of the PWC in the home aquarium.

i think some of you are missing the point here.

PWCs are not in question here. it's the frequency of water changes i'm asking about. it seems to be the norm from "expert" discus keepers that daily or multi-daily water changes are a must.

i'm asking about the empirical evidence on this frequency of water change.

if you consider these large city marine aquariums, you don't marine biologists conducting daily massive water changes. and their stock is much more sensitive to water quality. i also wonder how often or even if they siphon away any refuse.

nature does it with rain we do it with a python

well this would be more of a top-off wouldn't it? this brings up another important point. how clean is the natural environment of discus? i seriously doubt it's as pure as we make conditions in our home tanks.

Some breeders will change out 100% of the water 3-4 times per day and they are also feeding at least a dozen times per day. The results can't be argued with however. Phenomenal growth rates can be seen with ample amounts of fresh water and by filling their bellies with food.

while this is the exception to the rule, i've also seen phenomenal growth rates on a pair of discus stuck in an overstocked tank, fed only flake food, where the owner has never done a water change, and other fish are dying of disease. the only thing these discus had was a lot of space.

 

[bs6749]

And how often do they have JUVIES? That's the key.

 

[xyyz]

And how often do they have JUVIES? That's the key.

even then, consider their natural environment; exactly how clean is that water? i'm sure the water is full of decaying vegetation and contains a lot of run-off. i seriously doubt it's anywhere near the conditions we "claim" are the best.

imho, until and unless this is proven empirically, these daily, bi-daily, tri-daily 30-90% water changes is no more than an old wives' tale.

 

[bs6749]

even then, consider their natural environment; exactly how clean is that water? i'm sure the water is full of decaying vegetation and contains a lot of run-off. i seriously doubt it's anywhere near the conditions we "claim" are the best.

imho, until and unless this is proven empirically, these daily, bi-daily, tri-daily 30-90% water changes is no more than an old wives' tale.

Your basis is exactly where you are wrong. The Amazon River has some of the cleanest water on Earth. Any minute amounts of decaying matter don't even register when you take into account the volume of the river. The conditions where discus are found are pristine and the water is constantly being changed out. Think of it as essentially an infinitely changing water system with fresh water. Now try to recreate the same habitat for them. I think you'd be hard pressed to simulate those same conditions economically speaking.

You can believe what you want about it being an "old wives' tale" but if you speak to discus experts they will all tell you that there is relevance behind the rule.

 

[xyyz]

Your basis is exactly where you are wrong. The Amazon River has some of the cleanest water on Earth. Any minute amounts of decaying matter don't even register when you take into account the volume of the river. The conditions where discus are found are pristine and the water is constantly being changed out. Think of it as essentially an infinitely changing water system with fresh water. Now try to recreate the same habitat for them. I think you'd be hard pressed to simulate those same conditions economically speaking.

You can believe what you want about it being an "old wives' tale" but if you speak to discus experts they will all tell you that there is relevance behind the rule.

the amazon river clean? are you kidding? do you know how many toxins are dumped or seep into that river from mining, foresting, cattle ranching, human sewage, etc, etc? there's a pending case that might cost chevron billions for polluting the amazon.

species at risk because of the condition of the amazon, and the river is only getting worse.

i think that a true "discus expert" is an ichthyologist not a hobbyist. for example, take the "expert's" advice on feeding discus. they throw heavy protein diets at the fish, but in nature a discus feeds on:

"This species feeds predominantly on algal periphyton, fine organic detritus, plant matter, and small aquatic invertebrates."
Ecology and life history of an Amazon floodplain cichlid: the discus fish
Symphysodon (Perciformes: Cichlidae)

i seriously doubt the discus live in the river itself. they probably live in lakes and other smaller water bodies. and even then, the run-off from these rivers is polluted to begin with, so the water of these smaller bodies of water is polluted with some pretty nasty stuff. if discus are so hyper-sensitive to pollutants, then they would have all succumbed ages ago.

anyways, here's a link to the article. personally, i have more faith in scientists than i do hobbyists. i've started reading the article. hopefully, i'll come out knowing much more than i do now.

http://www.ufrgs.br/ni/vol6num4%5Cv06n4a08.pdf

 

[gzeiger]

I don't know of any controlled micro study of the sort you're talking about, but there has been an ongoing experiment for many years on a grand scale - the economy. It's simply not possible that such desirable fish would remain so expensive for so long if it were possible to breed them under less exacting conditions than what is practiced. The guy that accomplished it most easily would be able to trade the greatest volume and the fish stores would soon know who he was.

There have been many people like you over time who have tried to keep discus in all manner of water conditions. Maybe none of them constituted a controlled experiment, but taken together it's not unfair to consider the successful breeders as your control group and call the whole thing a scientific trial.

It depends what you're trying to do, though. I suspect (but don't know) that you'd have good success keeping these fish at much less frequent water change schedules, but I don't think you'd breed them nearly as successfully.

 

[bs6749]

Once again I'll repeat that those recommended water changes are for JUVENILES and not adults because hormone buildup in the tank has been shown to stunt young discus. Recommended changes for adult discus can be as little as 25% every 1-2 weeks to remove excess nitrates. I haven't changed the water in my 100g tank in the past 3-4 weeks (only topped it off) and I have a pair that has been spawned 9 times (the most recent was this morning) for me in the past 8 weeks.

 

[xyyz]

I don't know of any controlled micro study of the sort you're talking about, but there has been an ongoing experiment for many years on a grand scale - the economy. It's simply not possible that such desirable fish would remain so expensive for so long if it were possible to breed them under less exacting conditions than what is practiced. The guy that accomplished it most easily would be able to trade the greatest volume and the fish stores would soon know who he was.

There have been many people like you over time who have tried to keep discus in all manner of water conditions. Maybe none of them constituted a controlled experiment, but taken together it's not unfair to consider the successful breeders as your control group and call the whole thing a scientific trial.

It depends what you're trying to do, though. I suspect (but don't know) that you'd have good success keeping these fish at much less frequent water change schedules, but I don't think you'd breed them nearly as successfully.

breeding and keeping are two separate entities. i'm not so concerned with breeding. i'm more interested with the general upkeep of discus. for example, emperor penguins require extremely unique conditions found only in one location to breed, yet they're amongst the most hardy of animals considering the conditions they endure.

i hardly doubt you can consider the economy an experiment to prove the frailty of discus. the market set the price based on novelty. it's like any designer item; people pay for what it is, not because there's an overwhelming demand. there are plenty of discus out there. while i'm not expert in picking the best fish, i've seen fair stock that go for $10 for a 1.5" juvenile, which is the price-range of many fish.

breeders can't be considered the control group because they use the alleged "optimal conditions." both groups need to be identical sans the water changes.

Once again I'll repeat that those recommended water changes are for JUVENILES and not adults because hormone buildup in the tank has been shown to stunt young discus.

while this makes sense on a level of reason, do you have anything to prove the hormone influence on growth, or is it just another assumption breeders make?

if hormones are indeed an issue, you can always use amquel+. they claim it neutralizes hormones fish release.

this is what i'm gonna do. i'm gonna contact the author of that paper. he seems like a very well respected and highly educated icthyologist.

i'll report back with what he says.

 

[bs6749]

Personally I've done no research on the hormones, just bouncing back information I've obtained from the experts on discus forums.

It must be that there is some relevance to the "assupmtion" that I am making, otherwise how could you explain the claim that Amquel+ neutraizing fish hormones? If fish hormones weren't a big deal, why the fuss to neutralize them? Putting two and two together says that there must be some reason to neutralize hormones or to remove them alltogether. One of the reasons that I know of is because it stunts discus. Fish aren't the only living things that use hormones to tell them when to stop growing. Nearly every living thing takes cues from hormones on when to stop growing. If they didn't, you'd have cancer (uncontrolled growth). Plants that go dormant for example take cues from hormones on when to start growing after winter. Rabbits have an increase in hormones from increased sunlight in the spring and this triggers them to mate. The concentration levels of the hormones don't allow growth or other functions at certain critical levels. This is a relatively straight forward yet complex idea. I think you get what I'm saying though. If you want better answers you should visit www.simplydiscus.com They have discus experts that could answer your questions. Some notables include Jefferey Yang and Heiko Bleher. Maybe you could ask Jack Wattley in his monthly TFH (Tropical Fish Hobbyist) article and see what he says.

 

[xyyz]

Personally I've done no research on the hormones, just bouncing back information I've obtained from the experts on discus forums.

It must be that there is some relevance to the "assupmtion" that I am making, otherwise how could you explain the claim that Amquel+ neutraizing fish hormones? If fish hormones weren't a big deal, why the fuss to neutralize them? Putting two and two together says that there must be some reason to neutralize hormones or to remove them alltogether. One of the reasons that I know of is because it stunts discus. Fish aren't the only living things that use hormones to tell them when to stop growing. Nearly every living thing takes cues from hormones on when to stop growing. If they didn't, you'd have cancer (uncontrolled growth). Plants that go dormant for example take cues from hormones on when to start growing after winter. Rabbits have an increase in hormones from increased sunlight in the spring and this triggers them to mate. The concentration levels of the hormones don't allow growth or other functions at certain critical levels. This is a relatively straight forward yet complex idea. I think you get what I'm saying though. If you want better answers you should visit www.simplydiscus.com They have discus experts that could answer your questions. Some notables include Jefferey Yang and Heiko Bleher. Maybe you could ask Jack Wattley in his monthly TFH (Tropical Fish Hobbyist) article and see what he says.

the amquel+ it be a marketing ploy for one. while what you say makes perfect sense, ultimately it's all conjecture. with the discus none of it has yet to be proven. yes, i agree hormones are important/responsible for all sorts of biological processes. however, we assume the hormones are bad, but they might not be bad. and assume they are bad, or that they stunt growth or whatever. in what concentration do they have an effect? do the hormones disapate quickly outside of the discus? there are a lot of questions yet.

btw, i thought rabbits mated year round.

i created an account on simply discus. i also made contact with Dr. Crampton. He was nice enough to reply to my first email. I'll send him my questions or give him a call and ask him then.

 

[bs6749]

I thought it may be a marketing ploy, but considering that discus experts are aware of the hormones and they use Prime, I doubt that they would pick up Amquel+ to neutralize the hormones. They would rather do water changes than neutralize the hormones.

Hormones aren't bad, nor are they good. They are simply the means by which the cells know to grow or stop growing. I don't have any numbers as far as how much is secreted per fish but discus have been kept in captivity since the 50's or before and it's recommended to change out 50% of the water daily for juvies so a relative figure would be "pretty fast" if water should be changed that often.

Rabbits don't mate year round. Here in Michigan where we get feet of snow on the ground it makes little sense for adults to spend their energy breeding in October when their babies will starve in December with nothing to eat. Sure, maybe in captivity they'd spawn year round, but then again...my fish do that too when they normally wouldn't in the wild.

 

[SWerner13]

It just seems like you refuse to believe that you have to work hard everyday to keep your fish and expensive investment doing well. Although I admit I know nothing of Discus and am not trying to start anything. It just seems like this guy has given pretty decent evidence that these constant water changes work and for sure do not hurt and you argue semantics like when rabbits bread. Take his opinion into account otherwise why ask for it?