Live rock is a type of aquarium substrate made from natural coral reefs or other marine materials that are teeming with beneficial microorganisms. It serves as a habitat for various marine life, including bacteria, algae, and invertebrates, which help maintain water quality and provide a natural environment for fish and other aquatic creatures. When added to a saltwater aquarium, live rock can help establish a biological filtration system, promoting a balanced ecosystem. It is often used in conjunction with live sand and other filtration methods to create a thriving environment for marine species, enhancing both aesthetics and health in the aquarium.