What is a 6th level consumer called?

A 6th level consumer is typically referred to as a "tertiary consumer" in ecological terms. These consumers are at the top of the food chain and primarily feed on quaternary consumers, which are themselves carnivores. In some ecosystems, they may also be called apex predators, as they have few or no natural predators of their own. Examples include large animals like sharks or eagles, which can occupy this level depending on the specific food web.