Why do people wear Koi Dragon tattoo ?? ?

Question

I have seen people getting either Koi Tattoo or a Dragon. But what is a Koi Dragon Tattoo?

is it another creature from the Chinese stories ?

Answer 1

koi is a fish and a dragon is well literally a dragon.

depends on which nationality i guess.

japanese often regard tattoos as some kind of yakuza

Answer 2

A Koi Dragon is a koi fish that has made it to the point of a waterfall called the "Dragon Gate".  Once it reaches this point, the koi fish turns into a dragon, hence a Koi Dragon.  The story comes from a legend that dates back to ancient China.  

Check out my sources if you're interested in more about the legend - it's a cool story.