how many?

Ok, so I just added six cherry barbs to my community tank, 3 male, 3 female, is this a good number and ratio? or should I add more or specifically male or female?  It's a 55 gallon long currently housing 6 guppies, 2 gbr, 1 bn pleco, 1 dojo loach, 2 kuhli loaches, and 4 yoyo loaches, and 2 sae...