Discus and water changes

[Poustic]

Is it possible to keep (not necessarily breed) healthy discus with minimal water changes in a densely planted tank?

My plants and fish are currently very happy with a 20% water change every 2 weeks or so whenever I do regular cleaning, and the plants consume all the nitrates I add to the tank.

But I read a number of articles about having to do massive water changes for discus to prevent stunting their growth.  
If I add 4-5 discus in my 90 gallon "almost self-cleaning" planted tank, should I expect a lot more pollution?  Are those water changes recommended to keep nitrate levels down (in which case I wouldn't need that, would I?), or is there another reason?

[Julie]

Try to keep nitrates between 5-10.  20 is the absolute max I'd say.  Another member on the site has been keeping her discus in a nicely planted tank for quite a while.

For growth, lots of w/c - they need the fresh water.

Julie

[BigDaddy]

There's no problem keeping fully grown adults in a planted tank.  As long as the water quality is maintained (low nitrates... regular partial water changes) and the pH doesn't shift around (especially if tap water is way off compared to tank water), then you'd be fine.

For juvies, however, if you want to maximize their growth a bare bottom tank and very large waterchanges is the way to go.

[Poustic]

Thanks... I understand the need to keep nitrates low, but I sometimes get the impression that I could easily go for a full month without water changes as it is now (even though I don't).  I have to add plenty of nitrates to keep the plants alive, pH is constant with CO2, and oxygen levels are high.   So I am curious as to what else there is in aging water that needs to be removed in order to keep the discus happy in a low-nitrate planted tank?

[BigDaddy]

Are we talking about adult discus or juvenilles?

[Julie]

What is generally recommended is to grow them out in a bare bottom and then put them in a planted.


Julie

[Poustic]

I'm thinking 2-3 inches as they are relatively affordable.  What would make juveniles unhappy in a very low-nitrate planted tank, especially if they produce less waste than adults?

[BigDaddy]

They excrete a growth-inhibitor.  In nature, it's a biological defense mechanism against other organisms.  In a closed environment like an aquarium, it ends up stunting them.  The way to avoid that is with large water changes.

[Julie]

Survival of the fittest - not sure if the "growth inhibiting hormone" is a proven fact.  
The water becomes polluted which inhibitis their growth, not with ammonia or nitrites, but other constituents.  Nitrate is one of them, but there seem to be other factors involved.

Julie

[BigDaddy]

Yup... nitrate is a known growth inhibitor in most organisms (us too... so don't feed your kids a pound of bacon a day   :lol: ).

I thought I remembered reading something about Jack Wattley being convinced of a pheromone or other factor for juvenille discus growth.

[zapisto]

hi , i dont know for discus (or dont know enough to talk ) but i have 33g who have almost 4 years witout any water change.
tanks is heavily planted and have :
- a colony of A. staeki (cannot know for sure the exact number , but they are auto regulate themself, let say 12 or 15)
- 1 ancistrus
- 1 siamensis

and the experience continue

[NjOyRiD]

in a 65g, doing 50% water change weekly would it be okay for discus?!

[Poustic]

They excrete a growth-inhibitor.  In nature, it's a biological defense mechanism against other organisms.  In a closed environment like an aquarium, it ends up stunting them.  The way to avoid that is with large water changes.

Survival of the fittest - not sure if the "growth inhibiting hormone" is a proven fact.  
The water becomes polluted which inhibitis their growth, not with ammonia or nitrites, but other constituents.  Nitrate is one of them, but there seem to be other factors involved.

Ah ha!  So there is something else.  I hate doing things if I don't know why I do them, but now this is starting to make sense.  So, simply put, in a planted tank, one could do heavy water changes until they figure their discus are big enough, then slack off?   I guess with a bare-bottom tank you would at least avoid flushing all those good plant ferts down the drain.   :?

Would inhibited growth also cause health problems though?  Or in theory, if all the parameters are good, zapisto could have discus in his ecosystem experiment?

[BigDaddy]

in a 65g, doing 50% water change weekly would it be okay for discus?!

nJ:

That would be called a thread jack!   :lol:

[NjOyRiD]

ok well if its a thread jack I'll do another one with the same subject then

i just wanna know if its okay...

[Nelson]

in a 65g, doing 50% water change weekly would it be okay for discus?!

nJ:

That would be called a thread jack!   :lol:

BD...just so I don't make the same mistake someday, how does that constitute thread jacking?  He asks a question about discus and water changes - on subject I would think, or not? :wink:

[Evan]

The hormone released into the water is a hotly debated topic.  I don't know if it is true, and I do not know of any scientific studies that says it is. (there might be though)

I have read different thing including that adults release it to stop younger fish from growing up... I can't believe that.

The best explanation I hasve found is that it relates to the carrying capacity of the environment.  
In nature there is water everywhere, all of the waste, hormones etc released by the discus  in wild do not change the water.   In your tank they do.   When those levels reach a certain point that is too high to continue healthy growth it stops growing to avoid exceeding tha carrying capacity of the environment.  

I know there are a couple people with biology backgrounds maybe they can provide an explanation.

I agree with Julie.  It is best practice to put adults in the planted tank.   They do not need as much food and do not create as much mess.

It would still be advisable to vaccuum up the waste every couple days.  If your water parameters go out of line, youer fish change their behavior  or you have copeods you need to do more maintenance.

Also do not buy from lfs...

[mseguin]

If yuo give me a few days I will try to contact my developmental biology teacher on the subject.
I'm not entirely sure that kind of hormone would make a ton of sense biologically for some species. Possibly for species like discus, if there were a large number of discus in the environment the increased hormone levels in the water (i.e more competition) would cause them to slow down growing and therefore need less food to sustain themselves. This might make intra-species competition less severe, increasing survival for the species as  a whole. Personally, seems unlikely, as competition tends to favour the stronger individual rather than a population as a whole, and it definitely not make sense for piscivorous fish, IMO. Kepp in mind this is entirely specualtion on my part.

[Evan]

I don't think I should have used the word hormones in my attempt to explain. I am not sure what the right word would be though :roll:

I had some random thoughts after posting so here they are ... maybe they make sense.. maybe not.. :?

Pretend that this has nothing to do with discus.  Every environment can support so many of X species.  If the number of X is greater than the environment can support, something changes (ie not enough food)  and some X die.   IMO the variable that changes could be the reason that any of our fish die.

Your tank and maintenance schedule have a capacity of how  many fish can be supported. If the capacity is exceeded then the fish get stressed witch leads to sickness, stunted or slowed growth and death

Thanks for looking into this Matt, it will be interesting to see what you find out.

[discusFans]

Just want to say I am glad someone ask this because I've the exact same thought at the beginning when I start my planted discus tank. I read many articles and all of them suggest to do frequent water change for discus... but i though because they are not planted tank and so, water change is necessary for them. but now, i know there is actually other reason behind the frequent water change....