The Fisherman and the Sprat
A fisherman cast his net into the sea, and when he drew it up again it contained nothing but a single sprat that begged to be put back into the water. “I’m only a little fish now,” it said, “but I shall grow big one day, and then if you come and catch me again I shall be of some use to you.” But the fisherman replied, “Oh, no, I shall keep you now I’ve got you. If I put you back, should I ever see you again? Not likely!”
A little thing in hand is worth more than a great thing in prospect.