Espei/Hengel Rasboras would be a better option for a 10g. They look almost the same as Harlequins (the black marking is smaller) but don't get as large, topping out around 1.25 inches.
Exclamation Point Rasboras are even smaller at around 1/2-3/4 inches but are also a nice orange color with a black stripe down their side with a dot at the base of their tails (exclamation point!). These little guys tend to school together more often than the other really tiny rasboras I've had, too. If I was setting up a 10g, I'd put a school of these guys in it with your favorite color of cherry shrimp.