[xdude]

I had small fish pot and had 2 fish in that, it gave birth to many small fishes.And one day all those baby fish vanished, Will the mother fish eat its own baby?

Depends on what type of fish you had. I guess you had some type of livebearer fish like Guppy or molly. They normally don't eat babies unless there is nothing else to eat. So basically babies are off the menu as long as they are properly fed. And when it comes to Guppy only females eat babies.