If you get the aquarium nicely planted you could make the discus feel at home. It's not that small if you're not gonna keep crowdin' it. You can go with Ramirezii, Neon Tetras, Ancistrus sp, Otos, Corys, Paradise Fish, Pearl Gourami (great effect). Everybody sais Discus require much attention and stuff but it's not like that. There are articles that describe some interesting experiments on Discus fish that demistify this non-sense. Yes .. the water should be ammonia free, nitrites free and as low nitrates as you can, and 80F should be a minimum. But they are also very adaptable. Look what I've learned to keep in my 100 gals. I know it's very crowded and the species I have in are around 80% compatible but if you try hard you succed (I'm getting a 190 gal this week, I hope... I gave the order 2 weeks ago ... but it's being brought from Germany). Start with 3-4 Discus, some 10 Neons or Ramirezii, do some heavy planting, raise the temp and keep the water movement to a minimum and that's all. Let them grow, read a lot, learn how to make the thrive and then u can buy 1-2 more. Or ... by the time they grow big ... simply upgrade. I've always did that and I managed to succed with no casualties. The harder your task is the more experience you get. And that helps you a lot later. Good luck to you.
Discus are not easy fish to keep. They will not tolerate crappy water conditions. So, unless you're just a noob to the forum and not fishkeeping, and have plenty of spare time for water testing and changes, go with a heartier fish than discus.