Fluids conduct heat through convection which is a process by which thermal gradients establish flow of hot parts of the fluid which are less dense with respect to denser colder parts of the fluid. Convection is for example the reason that the top floor of your home can become unpleasantly hot when you are trying to keep the basement at a reasonable temperature: hot air is less dense than cold air and so it experiences a buoyant force and rises to the top. We have a demo experiment showing the flow set up by a thermal gradient in a liquid.