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RipSlider
Mon Sep 03, 2007, 12:00 PM
Hello all.

a house move means that I am going to have to take down my tank, and I've decided that it will be re-built specifically focused to be a discus tank.

I'm currently just starting out on the research stage, and the first thing that I've come accross is "Discus are fragile".

Everyone seems to agree on this, but so far I've not worked out *why*

discus need good water quality or they die. What I'm trying to find out is what specifically is it that kills them.

The reason for the question is that a 1,100l tank is a pain to do water changes on, and also I often get called away from home at short notice and my wife will only feed the fish.

So, i'm going to be looking to technology to keep the tank in good health.

if it's pathogens that kill discus, then lots of UV + lots of Ozone will deal with the situation.

If it's a chemical problem ( ammonia, nitrate, something else ) then this can also be dealt with, but I need to work out what exactly is the critical issue.

I know that, when looked at in the whole, there will be a combination of factors, but the fact that discus are so much more easy to make sick than most other fish seems to indicate that there is something particular that they don't like.


Second question: I'm looking to set up as close to an accurate biptope as possible for the discus, which will include species, plants, substrate and lay out of the whole tank.

Does anyone have any links to underwater photo's of discus natural habitats in the Negro and Amazon? Or articles on these habitats?

Many thanks indeed.

Steve

ILLUSN
Mon Sep 03, 2007, 01:01 PM
G'day Steve, some good questions there.
discus arnt that fragile, anyone who imports wilds will tell you they are very tough fish.

THEY DEMAND EXTREAMLY HIGH WATER QUALITY!
no NH3/NH4 or NO2 and trace amounts (less then 10ppm) NO3

when your water quality drops the fish's immune system drops and they fall victim to pathogens. if you want a low maintence discus tank you'll need excellent filtration, look at a VERY BIG sumped system, with ALOT of bio filtration (seriously concider a fluidized bed filter in addition) also you'll need some kind of a nitrate reducer in addition to a (or several) UVC's. That should help keep your water quality up, and any bugs down.

the only thing i think discus are more suseptable to then other fish are internal paracites (tapeworm, gill fluke nematodes etc) these are too big to be killed by UV so you'll have to do preventative treatment (i worm every 4-6months).

As for your second question discus dont usually live amongst plants, they live amoungst snags and drift wood in blackwaters, a biotype correct tank would use a substrate of light quartz based sand, LOTS of drift wood, the occasional E.bleheri/E.amazonicus and some floating plants (I like ricca).

squid put up a great post sometime ago about keeping discus with an "all bells and whistles" filtration system in a thread about breeding heckels, He'd be the man to talk to about your filtration.

RipSlider
Mon Sep 03, 2007, 01:31 PM
Currently in the midst of designing the new filtration system.

I can't use a sump as I don't like the additional noise that the weirs make, and becuase they're difficult to break down. Each of the following will be connected with ehiem break-taps so if anything fails it can be pulled out cleanly.

(Most of this stuff I already have - have 2x L46 plecs's and not willing to risk them in bad water...)

filtration:
2xeheiem Pro 3 ganged in parrallel but running at 2/3 flow so as to have
back up system if one filter dies ( This has happened to me, and was a nightmare)

1x Fluid Bed Filter - have one in place now. Makes for a rocky ride as the tank matures, but they're well worth it

1x ozone system running into a skimmer ( best way to vent the ozone - will kill most parasites - skimmer won't actually skim, but is easier to buy one than to build my own ozone injection and venting system)

1x bubble trap loaded with carbon - will remove any existing ozone and generate co2 into the water ( via carbonic acid breakdown ) which means that may not need injected co2

1x 30w UV tube Vectron 1 - is massive, but very functional

1x peat filter - This will be a filter filled with iron rich peat. The Fluid Bed Filter will generate masses of nitrate, due to all those bacteria. If oxygenated water passes through an iron rich peat fairly slowly, the oxygen will bind with the iron, and nitrogen will be released - simple bilogical way to eliminate nitrate and also helps with the plants as collated iron now in water.

I have most of this stuff now, I just need to work out a way of plumbing it all together in a fairly fair safe way.


I have essentially an identical system in place at the monment, minus the reserve filter and the ozone, but with more UV. I do one water change a month, or maybe every 6 weeks, and with that regime, I never hit more than 5ppm nitrate and no nitrite or ammonia ( now that tank has matured ) and most of the time it's un-measurable.


OK, next question - do Discus live in actual "black water" conditions? I thought that very few fish could live in black water, and only really hardy things like swordtails could cope?

Has anyone ever seen a water sample anaylisis of the water where wild discus are caught? What sort of stat's were they?

lastly, are there any key books that everyone swears by that I should read?

Many thanks

Steve

dwilder
Mon Sep 03, 2007, 08:46 PM
one thing to remeber is its not just nitrates to watch for thats just a guide number that helps keep the water in check,thereare other organic debris in the water that tend to lower water quality.unless your tank is extremly under stocked and heavily planted your discus will probably suffer. also the water of wild discus really only matters if your getting truly wild fish if you obtain home breed fish you need to find out the specs of the water they have been raised in.in all i would suggest more water changes

apistodiscus
Tue Sep 04, 2007, 08:28 AM
Drill the tank and there won't be any noise from the weir. Nitrate is actually not that poisonous to fish. Ammonia and nitrite are the killers.

I wouldn't keep my l46's with discus. A pH 6 below six and your cats will do the back paddle bit your discus will only really colour up fully at a pH of 5.8 or thereabouts (if you going for wild caught fish).

Are you planning to keep wild discus or once bred in captivity? Wildcaught once are a hell of a lot more delicate and I wouldn't advise a first timer to keep them. You'll need to worm them (Flubenol is good and so the new stuff from JBL) and they can be very fragile especially if your water parameters are fluctuating.

Captivity bred fish are much hardier, Try to get fish from either Germany of the Czech Republik. Some Asian fish are good but I don't like the shape they are bred to (personal opinion, if you like them, keep them).


Discus are not that hard to keep. Another urban myth. It takes a lot more to kill a discus than to kill your average tetra. Get decent quality stock and they are no harder to keep than any other fish.

As for water parameters in the natural environment. ph is around 5-5.5, conductivity is below 120 micro siemens. Temperature about 28 degrees in one meter of water. This, of course changes during the rainy season where the temperature will drop a couple of degrees. The only reason why discus are kept at 30 degrees is to help them keep the fat from all those beefheart mixtures liquid in their blood.

RipSlider
Tue Sep 04, 2007, 11:53 AM
Thanks for the advice guys.

I'll be definately going with captive bred fish. There is a local breeder who has been recommended, which I think will be a good place to start, as it means I should be able to hit his water quality settings fairly easily.

Right now, I'm struggling to decide what sort of aquascape I want to set up, do I want a soil/leaf/mud bottom with loads of bog wood, which would seem to be their natural enviroment, or a more planted tank.

hmmm... it's a difficult one.

On the subject of the fish themselves, is there any difference in hardiness between the various different varieties of discus? I.e has breeding of specific lines or colours led to weakness, similat to what has happened with Endlers?

Many thanks

Steve