For years scientists told us what we wanted to believe - that fish have short memories only lasting one lap of the fish bowl. Now the truth has got out. They are intelligent creatures who can learn to do things and can even deceive other animals. Once attacked, if they escape, they remember which predator tried to kill them. Unlike humans, however, there is a cost when they use their intelligence. If they are given one fish for food they are very efficient in catching it, but if given two types of prey they apparently become confused and their effectiveness declines. Fish interact in a social way. They recognize familiar others and modify their behavior accordingly. Siamese fighting fish will take advantage of a weak fighter by observing fish fights and readily attacking the weaker fish. Fish that clean others act busy when potential "customers' are watching. In a way they advertise. The myth about fish having no memory or even intelligence is most likely promulgated to ju...