Han riu or not

Here is what I gathered on information about the legendary dragon Han Riu.

It has stripes of 9 different colors.
Is more then 40 feet long.
Tries so hard to reach heaven, but never succeeds no matter how long he/she is.

I didnt find any depictions. I just had this description.
And I found it odd.
So there is that elongate being with a whole color spectrum that always tries to reach heaven, but fails no matter how hard it tries.
Sounds like a rainbow to me.
If that is one of the ways the japanese tried to explain rainbows, I would be very happy.

COULD BE THAT I AM COMPLETELY WRONG THOUGH!
So yeah. My interpretation of han riu.