A fish dream symbolizes wealth and abundance. Catching a big fish means success in a major business or career. Fish leaping out of water hints at rising wealth or good news incoming. Pregnant women dreaming of fish is interpreted as a conception dream for a healthy child. Losing fish in a dream warns of financial loss.
Animals appearing in dreams — as in "Fish Dream" — often symbolize instinct or a suppressed impulse in Jung's theory of Archetypes. The specific animal and the emotion it evokes in you both shape the meaning far more than a generic dream dictionary entry can.
What was the first emotion you felt when you saw that animal in the dream?