Substrates and Live Rock
Live rock is rock taken from the ocean which is usually encrusted with Coralline and inhabited by marine organisms. The term is used mainly in the aquarium trade where the rock is valued for the diversity of life it can bring to a closed marine environment. Live rock is also used in saltwater aquariums as a main source of nitrifying bacteria, important roleplayers in the nitrogen cycle that processes waste from aquarium inhabitants into less toxic forms. Live rock, especially when encrusted with multiple colors of coralline algae, can also be a major decorative element in a saltwater aquarium. It's often used to build caves, arches, overhangs, or other structures in the tank.
where it has become detached from the main body of coralLive rock is harvested for use in the aquarium trade; it may be collected wild from near reefs, or small coralline rocks may be "seeded" by an aquaculturalist in warm ocean water, and harvested later. Live rock harbors a wide variety of corals, algae, sponges, and other invertebrates, when they are collected. Not all of these are desirable, and through a process known as curing, live rock is usually kept in observation tanks for several weeks to attempt to remove all undesirable organisms before the rock is placed in a display aquarium. Sometimes corals will be seen attached to live rocks. Live rocks are made of the calcium carbonate remains of corals.