Join Date: Oct 2016
Location: Jeonju, South Korea
Your tank is not really suitable for discus or for adult angelfish-- adults get relatively large and they need swimming room. Although your tank has a large water volume, it has relatively little surface and swimming areas.
You can take advantage of the height though be choosing fish that inhabit different areas of the water column. Since you mentioned angelfish and discus, I assume you are interested in S. American cichlids and will prepare soft water, so this is what I might do.
I would hardscape with tall, branching pieces of wood that offer a lot of hiding places and plant broad-leaved plants along the base and moss on the branches. I would also plant the back and sides fairly heavily with taller plants and sparingly add some floating plants like salvinia or frogbit (nothing that will block the light or grows too quickly)
I would stock with a pair of Bolivian rams that will be in the lower strata of the tank. I might pick a small school of a small tetra species or several small schools of small tetras-- lemon, flame, glowlight, black phantom-- for the mid-water region, and a group of hatchet fish for the top or pencilfish if I could find them. I would also add some oto cats and maybe some small wood cats. I would consider a small pleco species if I was not interested in breeding the rams.
That is what I would do with the tank. However, you should take your time and consider exactly what you want. If there is a fish that you particularly like, take some time to research what it requires in terms of water conditions, aeration, substrate, cover and food. There are formulas you can find in terms of stocking, but you need to consider the adult size of the fish, whether it is solitary or social, and the activity level of the species and then consider the size of your tank.