Zynga has introduced an in-game message sending feature to FishVille. The system is fairly similar to that of FarmVille, in that you can create a free sign board with whatever message you’d like to create to be placed in a friend’s tank (yes, sign board messages are public in FishVille just as they are in FarmVille).
However, the game’s underwater nature lends itself to another type of message: the message in a bottle. In this case, the messages are private, meaning that they can only be read by the owner of the tank, allowing you to spread whatever fishy rumors you’d like without the fear of getting caught. Or just confess your never-ending love and devotion to your significant other in-game; I’m sure that would work too.