An aquatic food web is a complex network of feeding relationships among organisms in water ecosystems, such as oceans, rivers, and lakes. It starts with primary producers like phytoplankton and aquatic plants, which convert sunlight into energy through photosynthesis. These producers are then consumed by primary consumers, such as zooplankton and small fish, forming the base of the food web. As you move up the food web, secondary consumers, like larger fish and crustaceans, feed on primary consumers. Finally, top predators, such as sharks and bigger fish, occupy the highest level, maintaining the balance of the ecosystem by controlling the populations of other species.