What does it mean if you dream about a snake in a fish tank?

Dreams seldom have specific, discernible meaning. They are our subconscious mind's way of processing and filing information. This is especially obvious if you understand that we only remember dreams that occur just before we awaken, but that we spend hours dreaming every night. It is as inaccurate to place meaning on a single dream as it is to assume that you understand a book when all you read was the last couple of pages.