A rainbowfish is read as beauty that is meant to be shared. Dream books tie its shining scales to the question of what you give away and what you keep for yourself.
Does the traditional reading fit your dream, or did it mean something else to you?
My Cosmic Code has a private dream journal. Write a dream down and the app picks out the symbols in it, shows what dream books say about them and, over time, which words recur across your entries. The journal is stored on your device only.