A potent image in mythology is the Salmon of Knowledge, which signifies knowledge of other worlds (the lands beneath the sea) and of otherworldly things. This conforms to Shamanistic belief that creatures have the ability to visit other dimensions. In common with most fish when they appear in dreams, the salmon signifies our basic urges most often the need for survival. By being able to put in effort we reap the rewards of our actions. In modern medicine the omega 3 oil that is in salmon is a powerful brain food. When the salmon appears in dreams we may need such a substance or be being warned that we need to pay attention to our intellectual pursuits. The salmon signifies abundance and masculinity and is also phallic. In its fight to mate by swimming upstream it can also symbolize the sperm and may do so in men's dreams. Often a salmon can appear in a woman's dream as a symbol of her wish for pregnancy, whether this is a conscious wish or not. You might also like to consult the entry for Fish as well as the information on Shaman in Spiritual Imagery in the Introduction.