the biggest difference between discus and most other fish is that if you slack off on your tank, they are less forgiving. young discus are a lot of work and your tank is too small for adults. why not try angels? they are happy in groups of 3 or 4. if your going to try them anyway, then do your research. there are old myths and some bad/wrong info on the net. ask before you do something, or you'll end up with at best stunted, sickly looking fish.