I want to design a simple fish game in wich the bigger fishes eat the smaller ones. The grafics and player movements went incredibly easy; the problems came when I've tried to simulate the movement of real fishes. I had some ideas but my fishes move incredibly unnatural. I realy need an algoritm for it.

Steering Behaviors for Autonomous Characters

Thank for the link, it realy gave me lots of ideas to continue. I will post the final code as soon as possible! And also the game :P

Boids