Aquariums

There's hundreds  of aquarium choices for Discus fish and it really comes down to budget and space.  

Whatever fish tank you choose it will need a sturdy cabinet, best to buy that with the tank if possible but it will also need a very sturdy floor.  At 1 kg per litre the water in your tank can quickly weigh in the hundreds of kilograms.  With glass, rocks and cabinets, a good sized fish tanks could reach several hundreds of kilos in weight.  Floorboards wont take it (depending on how big you go).  So consider everything before your spend your money.

There is many figures around the web about the number of litres of water you need per adult discus.  That depends on many things which makes a specific figure difficult to calculate.  Discus do not do well in small groups, you need at least six, preferably more.  The larger the group the better for a number of reasons.  And its best to add them all at the same time.  So for tank volume you will need hundreds of liters, again the bigger the better. I was once advised that I could keep 40 adult discus in a 550 litres (so 13 liters per fish).  That may be possible but I dont have the time for the constant water changing and overstocking is the fastest way to get problems in your tank.  So going on actual experience I have 18 not quite adult Discus in this tank.  Around 30 liters per fish.  Theres a few other fish in there but not many.  I did have more in this tank and issues arose, reducing the number has definitely made things easier.

 
As Discus are tall fish, I find the deeper tanks suit them better and from an aesthetic point of view you can get a much better look.  This can offer cleaning issues if you tank is too deep however. 

 
Most tanks are glass, some are acrylic, they can all get scratched quite easily.  Some are rimless others have cover glasses.  Rimless look very nice but you will forever be topping up the evaporation (Discus like 30 degree water).  Discus are easily spooked and can jump, which is an expensive event, so if you like the rimless look, which is very nice some kind of cover is advised.  This then spoils that look.  If you're buying with cover glasses (usually sliding) make sure you can get you equipment to the water as the bracing can limit or restrict access for filter intake/outtakes and wiring.  
 

TOP TIP - If you are planning to keep these fish, keep these fish.  Plants, other fish, the look of the tank (rimless etc) should all be secondary to keeping these fish properly.  Trying to do it all just makes things very difficult.  A covered tank is a good idea as they will jump at some point and you will lose a fish if you like the Rimless look but dont get a cover.

You may come across Optiwhite glass, basically this is low iron glass which can increase the light transmission, it removes the green sheen that some tank glass can have.  If you want your discus colours to shine through your crystal clear water this is definitely worth considering although it will increase the cost.

Silicon colour can also be important, black is better, clear can discolour and show algae.
 

You may also have the option of a sump (see filtration for more details), its probably the best method to filter a tank providing large volumes for media, increased water volume and you can put other equipment in it, out of view, so your main tank is just for the fish.
Some manufacturers will build a tank to your size and cabinet specification, this is highly recommended if you can go down that route.  You can even pic a background colour.
 

TOP TIP - if you have sand be super careful when cleaning your tank.  Sand will scratch with the lightest of pressure when removing algae.  This is very difficult to fix once done, and you wish you were more careful everytime you see that scratch.