Dreams involving fighting or struggle, especially alongside a parental figure, often symbolize conflicts or challenges in your waking life. The giant anaconda and then the crocodile could represent overwhelming fears or threats that you feel are difficult to overcome.

Your father in the dream may symbolize authority, protection, or guidance, and the act of fighting together suggests a shared struggle or challenge. The transformation of the anaconda into a crocodile might indicate a shift in the nature of the threat, possibly reflecting how problems can evolve or change form in your life.

Running slowly while trying to save him can represent feelings of helplessness or frustration in your ability to protect those you care about or tackle issues effectively. This could reflect real-life situations where you feel like you're not able to act swiftly enough in critical moments.

Consider reflecting on any current situations where you feel overwhelmed or unable to assist someone you care about. This dream could be encouraging you to confront these feelings and find ways to address the issues at hand, whether that's seeking support or finding new strategies to deal with challenges.