I went few times at the Drunken Fish when I lived in IFSC.
Great place to go in couple or with friends. The place had kind of 4 different atmospheres.
Take away (for lunch) great and cheap, Hypster Irish Pub, lounge area to chill and restaurant.
In the restaurant, try the open area with windows, more enjoyable than the close one who can be really noisy if big groups.
The food is absolutely GREAT! Go for the Bibimbap or the Korean barbecue!