Those are still fairly young, aren't they?
They get longer bristles when older.. the males do at least. I think the coloration is a little different when older too. Genes also play a part in it.
Current fish (includes all 3 running tanks): Polypterids, severums (of which I raised from eggs), gouramis, plecos (gold spot ones & a gurupa), loaches (zebras, yoyos, & a kubotai), macculocchi spotted silver dollars, an African butterfly fish, & Ctenopomas (a leopard & an ansorgii)