I suppose they are a bit rare, I've only seen yellow on a male plakat and a few females in my town. I wish I could find a yellow veiltail, they are my favorite tail type! Pineapple is sort of yellow, except pineapple colored bettas are more of a darkish yellow with black outlining each scale. They're very pretty, but I prefer a more sunshine yellow =)
My Current bettas:
Sullivan- Orange rose tail halfmoon male
Daisy- Mustard Gas (black and yellow) veil tail female
Milton- Teal butterfly halfmoon male (mom's betta)
DFTBA to nerdfighters working to decrease world suck!