Eating fish in the office is a NO NO, for both fish and fish eater.
Picture this guy who always katias every new fish in the pond, and when the fishes start talking about this experiences, not nice....
When the fish moves on and starts dating someone else, especially your boss, and your boss knows your past, not nice.
If eating fish at the same place of work but different towns/departments and you do not get to see each other often, not a big problem, but nowadays women have mastered the game, they are the 'users'