Dream about dead betta fish is a metaphor for abundance, plentitude, fertility and prosperity. You may still be trying to understand some concept or emotion that is still in the primitive stages. It is time to get serious. This unfortunately draws attention to feelings of guilt and fear of being caught. You are projecting yourself onto a person or animal being tortured.
Dead betta fish dream is a warning alert for a female in your life who is emotionally cold. You feel trapped or suffocated in a situation or condition. You may be overly conscious about your appearance and beauty. The dream represents components and various pieces that composes your life. It is time to let go of some past grudge, guilt, or resentment so that you can move ahead with your life.
If you dreamt about dead betta fish:
You may actually begin to question your motives as to why you are in a relationship with them in the first place. Not because it is not going well, but because you are not sure where it is going, and so feel a little cheated out of having something positive to aim for.