Dirty Fishtank 

A women with a smelly vagina. One who omits an odar out of her vaginal area, has and kind of wierd secretion, and/or has vaginal bleeding.

"Do you smell that, I think that girl has a dirty fishtank!"

Dirty Fishtank by PzzKng March 3, 2007

Dirty fish tank 

When a female gets oral sex while taking a dump in the upper tank of a toilet.

It’s like a female blumpkin mixed with an upper decker.

Sara gave me a blumpkin last week. I returned the favor by hooking her up with a dirty fish tank in the restroom at the mall.

Dirty fish tank by Ann_Archy September 11, 2018