how long does it take for stocky to take the natural source of food

[JackM]

They don't pick up every pebble on the streambed, but may pick up debris that in some manner has the pattern of food whether lying still or in the drift. The pattern is instinctive, not learned. They don't learn what is good to eat by raw trial-and-error, though their instinctive behavior may become refined somewhat through a rudimentary learning process. But as my example of the wild fish that can be coaxed to the surface by a piece of stick demonstrates, they never lose the instinctual urge, not even temporarily. Thus, when put into the stream, they will begin finding edible objects readily by pursuing the impulse with which nature endows them.