You should first check to make sure that your game is not paused; however, this problem is most frequently caused when people try to make the game progress more quickly by adjusting their device's system clock. While that sort of "time travel" is a popular way to speed up game play, real-time games rely on the accuracy of the computer's system clock to operate properly. Unpredictable results can occur if adjustments are made to the clock, especially moving the clock backwards in time. Different games will respond differently under those circumstances, ranging from minor statistics anomalies to killing whatever is living in the game. Virtual Families has a much more complex real-time engine than Fish Tycoon, and you're much more likely to see problems with it when adjusting the system clock.
While many people do adjust their system clocks to speed up play, doing so affects far more than just the games. Every application in your device is affected, including the file system and other system applications. For all of those reasons, we do not recommend changing your device's clock to speed up game play.
There are a couple of ways to resolve the problem: You could wait it out and see if the game recovers or you could just delete the malfunctioning game and start over. Good luck!