A euphemism for I don't give a shit. Especially useful in response to unsolicited bragging or otherwise useless information. Stems from Costanza in The Opposite episode of Seinfeld.
Seinfeld: Chicken salad's not the opposite of tuna. Salmon's the opposite of tuna. Cause salmon swims against the current and the tuna swims with it.
Costanza: "Good for the tuna."
Seinfeld: Chicken salad's not the opposite of tuna. Salmon's the opposite of tuna. Cause salmon swims against the current and the tuna swims with it.
Costanza: "Good for the tuna."
douche: "I worked really hard this weekend, but it payed off -- my boss said I did a great job!!"
dude: "Good for the tuna"
dude: "Good for the tuna"
by ChrisGGG November 07, 2010