Artificial Reef Rock is a man-made rock as opposed to a natural reef rock, it is used to create underwater structures in marine aquariums and typically built to promote the growth of marine life such as LPS and SPS corals. Artificial rock is popular amongst hobbyists as it comes in a variety of shapes and sizes making it easier for people to create their perfect aquarium feature. One of the main benefits of artificial reef rock is that it does not come from the ocean there so is zero possibility of introducing pests or nuisance algae into your aquarium.