Planted Tank Guru
Join Date: Jul 2010
Location: Huntington Beach, CA, USA
How many fish may depend on what you want from the fish compared to how much time/work you want to do. Small fish can be trusted to do okay in larger numbers than larger. If you don't mind them needing to be moved out as they grow, a whole lot of fry can go into a ten.
The limiting factor is usually the way you keep the water qualities. That often means changing water. More fish, more work, less likely to get the full quality out of the fish.
The setup you suggest should work if you watch the water and do the testing and work needed. Fish may want things but they will often live well without what they want.