A long while ago my friend http://galaxy-of-stars.deviantart.com/ has
drawn http://galaxy-of-stars.deviantart.com/art/Two-Underwater-Friends-629722896
So I decided it's best be appropriate I drawn those two primarinas and showing
a bit of the gender differences and some headcanons, there are some changes
to my original headcanons too.

Male primarinas are more 'masculine' than their female counterparts and has less of a
curve than females. They do have extra fish fins while the females do not.

The length of the hair retains different sizes for both genders and it is optional to change
the hairs in the salon(sadly I doubt they would implement this in a game but that
comes along with the artist's imagination and creativity of course).
Primarinas can have multicolor hairs(like for Haupia's having tri colored hair)
as their dominate or recessive trait.

The delicate fabric they wear is made from fish skin, when they are torn or
tear off, they do have more of a regeneration process do to their 'fairy' typing.
Scales are easily replaced when they are torn off or worn out. Because of
this they are considered best used as special walls to counter special attacks.
However, due to the fairy typing they are incredibly frail to physical attacking
moves, like the upper part of their body can get scratches or marks if not
treated properly.

On their heads the starfish comes in different varieties as they're pretty much
used for decoration. The starfish that are attached to the Primarina's are actually
dead husk/shells of staryus. The most gorgeous male primarina has likier chance to have
multiple females in a colony which is called a 'harem'. A male primarina rarely get into fights as
they use their vocals to win the hearts of female primarinas, however trespassing their territory
without permission or trying to severely go after their females. They are most likely spar.

Artist Note: This could be a good reference for
Haupia, since I always love to do shade and do
lighting affects on her. Yes the apple ribbon
she's wearing is a leftovers. This is a pretty
optional accessory as she only wears it in battle.
Outside of battle however she always wears her
friendship bracelet that her mate gives her on
the tail and has a pink ribbon on her that was
given to her by her foster father. Kale is slightly
taller than Haupia in comparison to side to side
next to her which was really fun to do.

Kale(c) http://galaxy-of-stars.deviantart.com/