The thought of a person or a thing that mentally crawls inside you and interferes in your day-to-day activities. It consumes your every thought and hinders your way of life. Much like the fish it was named after (the Candiru) which crawls inside you and lives inside, so do these thoughts.
George: What’s your problem?
Izzie: My problem…is you. You’re my penis fish.
George: Your what?
Izzie: You’ve crawled in and latched on, and now I can’t move, or talk, or think, or even pee without the necking feeling that something is eating through my organs!
the kandiru fish of the amazon. called the 'Amazonian Penis Fish' because of it's rather unsettling habit of occasionally swimming up the urethra of an individualtaking a piss in the amazon. it then proceeds to secrete it's spines into the urethra, and embeds itself in the urethra, mistakenly thinking its latched into the gill structure of another fish- its usually prefered prey.
A fish that swims into your penis and eats you from the inside out. It will cause extreme discomfort, possible insanity, extreme fatigue, cravings for pickles with chocolate, and reoccurring wet dreams about orange unicorns.
Brian: why is John being so weird, he's eating pickles with chocolate and screaming about unicorns in his sleep...
Kyle: he's got a penis fish.
Both: *begin to intensely cry*
Brian: WHY COULDN'T HE HAVE JUST ONE MORE YEAR?!? WHY GOD WHY?!?!
Kyle: it's too late brian.. he's gone..
John: *orgasms violently and dies*