A car gets "fish tanked" when some idiot leaves their sunroof open during a terrential downpour. The best form of the "fish tank" is when water flows out your door when you open it.
Wow, it sure was raining out. Chris's cargot fish tanked real bad!
(verb) to bend a girl over a fish tank whilst delivering anal sex to her. Mid-motion remove the lid of the tank and repeatdley dip the girl's head in and out of the tank all the while still ramming the girl in the anus.
I got this girlround last night and fishtanked the shit out of her!!