One clownfish not growing

[Eradliff]

Hello, Ive had a pair of clownfish for a couple of months and I have noticed that one of them is getting bigger while one isnt, they were the same size when i got them but now the size difference is decent, does anyone know why this could be? the larger is probably 2 inches now ( still small I know) and the smaller is probably half of that.

 

[The_Paradox]

Male will stay pretty much the same size and female will get much larger.