hi i have only had 2 discus for a few weeks and was wondering what i could keep with them i plan on having 6 discus in a 4 foot tank with 10 cardenal tetra 10 cory cats 10 harlaquin rasboras 10 dwarf neon rainbow fish 10 marbel hatchets and 7 glass cat fish and maby a golden nugget plec and ill be putting a sump on my tank to help manage the nitrates. will all all of these be ok with the discus ?