Let me just say this, i have a 55 gallon. And in this 55 gallon
FW tank ive had for a year, there are : 1 - 8" pleco, 1 - loach of some type, 2 -blue gouramis, 1 - tiger barb, 9 - rainbow tetras YES i said 9!, 5 - danios, 1 - striped rafael, 1 - orange gourami, 1 - neon tetra, 1 - "silver dollar" fish, 2 - paradise fish, 3 snails.
That is a total of about 30 fish and in my own opinion, its overstocked but my parameters are always perfect and i do a 30-40% water change every 2 weeks.
You have to keep it up and as long as you do so, you'll be fine. But you have to be conscientus about it.. I run two strong power filters and I have a bubbler in the rocks to keep the water in good motion and aerated.