In the rules is stated that a small fish gets eaten by a predator when the predator moves to the same space with the smaller fish. It also says that a small fish cannot move to the same space as another small fish, and if the player is unable to move small fishes indicated by the dice, any other small fish can be moved. But I cannot find anything about moving a small fish to the same space with a predator.
So, can a small fish rush head on into the mouth of a predator? In that case one could feed other players fishes in some situations. Intuitively I'd say it shouldn't work like that, but I'd like to get confirmation for it.