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I do not beleive so, although I have heard it. I have seen goldfish know the hand that feeds them, like when you reach to the back of the tank, they go there. I would not think so.
There is a difference between memory and Pavlovian conditioning. I feed my fish around 8:00am and 7:00pm, at both times they are hanging around the top of the tank gulping at the water. They don't remember me, they just instinctually head for the top when I am around the tank.
I believe this is true and agree with JamesMJ2 that this behavior is nothing more than Pavlov Conditioning. I have heard the length varied between 2 and 4 seconds in different publications though. Either way, it is short. Look up Pavlov's Dog on the web to see more about it.
There is a risk that the fish are more intelligent than you. My fish have conditioned me to feeding them by frantically swimming up and down the long side of the tank when they see me. They have trained me well as I give in to their puppy dog eyes and feed them.