Can fish remember? Anyone who has ever owned an aquarium knows how quickly fish learn to associate wiggling fingers with food.
What's even more memorable is that there is a lot of research out there on fish memory. Despite the fact that the Internet abounds with rumors that goldfish can only remember something for a few seconds, experiments show that once taught to perform a certain task in response to a certain stimulus, goldfish will remember the task for several days.
Another example of fish memory is the way salmon use their sense of smell, also known as olfactory imprinting, to return to the same stream they were born in during mating season. Some species, like the arctic char, can remember the smell of their siblings for days, and others can remember and recognize specific fish who are aggressive opponents.
And how about all the fish that encounter new types of prey, become efficient at feeding on it, and then remember their new skills up to a month later when they encounter this prey again?
Basically, fish learn and remember where their nest is, what the boundaries of their territory are, and where their mates, food, rivals and predators hang out. They might not look like it, but fish can have pretty good memories.