You cannot keep convicts in a 10 for long. Don't even bother trying. Harlequin Rasbora, glowlight tetras, neon tetras, bleeding heart tetras, guppies, endlers, killifish all do well in a 10. Many community fish will work out for you. The larger or more exotic ones need more space, more water, or more length or all three at once.
I know they all seemed to jump at you like it was a terrible idea, but they are just trying to help you out...but I got my first tank I wanted sharks, I asked the people at the store about sharks and they said at least a minimum of 55 gallons is recommended for any kind of "shark"
I am also using this tank to prove to myself that i can maintain a healthy community before I go out and dish out a bunch of money for a larger tank