According to Jung, fish represent the deepest levels of the unconscious mind.
He suggested that this was due to their cold-blooded nature and their early evolution on earth. Dreams that feature creatures of the sea are therefore indicators of deep-rooted instincts, fears and anxieties that have not been fully uncovered in waking life. Jungians think that fish symbolize a spiritual quest or seeking, whilst other dream interpreters claim that fish symbolize abundance and fertility. Fish are sometimes also recognized as a symbol for Christ and Christianity. Given all these possible interpretations, it is worth focusing on the condition and appearance of the fish and other sea life in your dreams so that you can discover the personal meaning they hold for you.
There are a number of possible interpretations for dreams that feature reptiles and amphibians but in general they suggest danger, energy and the powers of healing and transcendence.
If you are scrupulous in remembering the kind of behavior displayed by the creature in your dream, it should help you identify which feeling or emotion is applicable to your current situation. As with all dream interpretations, when it comes to underwater dreams that feature fish, reptiles and amphibians, it is also important to consider whether your unconscious is using word-play to get its message across.