look up any word, like fleek:
 
1.
an emoish girl. The biggest whore ever. Dies her hair a new color every week.
M: Did u see rainbow fish this week?
S: Yea that whore has black hair. Eww and she keeps talking to Freddie.
by bettywhore May 22, 2008
 
2.
A person who is pretty damn awesome, there so cool they can wear a rainbow and be cool hence, rainbow fish.
He's is such a rainbow fish, even though his cloths make him look like a rainbow..." "Damnnnn what a fine Rainbow Fish, she's sucha bitty
by :-))))) tripled chin June 13, 2010
 
3.
male equivalent of a fruit fly
Person 1: that guy is a pimp, look at all those females with him

Person 2: oh him, naw he's a rainbow fish

Person 1: T_T
by highposition December 26, 2010
 
4.
When a large woman, preferrably black to be politically correct, has a group of men, each wearing a different colored condom, all pleasing her fish at the same time. Such an act must be done for her to recieve pleasure, as a normal penis would not supply nearly enough meat to fill her fish.
Randy: DAMN that bitch is HUGE

Jake: that's DEFINATELY where i parked my car!

Zach: lets rainbow fish her all night long!

Dan: GENIOUS GENIOUS GENIOUS!
by DsTRO June 13, 2004