I'd say male.. granted it does have the mustard yellow color of a female but female's are not usually that colorful and in the first pic if you look just behind the gill you can see the spots are starting to appear. Mine is doing the same thing.
i'd say female and that will also explain the small size and growth rate. my female is jsut now at the 6inchish mark and i got her last sep. she hides allot also. you may have all females. i think i went through 5-6 before i finally found a male.
and MudFrog....my male loves sinking carnivore pellets. he'll take 10 at a time sometimes and he is just 4inches.