What is Live Rock?
Live rock is rock from the ocean made from carbonate minerals such as aragonite. Most live rock is harvested from reefs in the Caribbean or South Pacific areas. These rocks contain coralline algae, bacteria, and small invertebrates. These organisms are why the rock is called “live rock.” The rock itself is from long dead corals but play host to a multitude of marine organisms. These organisms and bacteria can be beneficial to an aquarium if treated properly. The live rock needs to sit in the saltwater aquarium and be “cured” before fish or invertebrates are added. Curing is simply the process of the organisms on the rock that did not survive the collection and shipping process to finish decaying. This process produces many toxins that are unsafe for life in the aquarium. I have read that this is quite a stinky process and can last 3-4 weeks. To know when the live rock is done curing, a simple ammonia test must be performed. When no more ammonia is produced, your live rock is cured and it is safe to add fish. These tests can be done with test strips or dropper bottles of testing solution.
There is also “base rock” that can be added to an aquarium. This rock is simply live rock, but without the living organisms. This rock is cheaper and can be placed with live rock in the tank. The live rock will populate the base rock and make it “live” in a short amount of time.
Live rock is not only important in that it provides beneficial bacteria and other life that contributes to the overall quality of the aquarium, but also provide refuge for fish and invertebrates.
Choosing what types of live rock we would like in our tank will require a fair amount of research. Price will play a big part for us, but appearance also. Each type of rock has a different appearance. Choosing what you think will look best and rearranging it in the tank is known as aquascaping. We also want to make sure that we buy rock that is harvested from the ocean floor where it has broken off during storms, rather than harvested directly from the reef. Types of live rock are Fiji, Caribbean, Melanesian, Nano, Tonga, and Pacific to name a few.
There is also live rock that is eco-friendly, as it is not harvested from the ocean. It is man-made in a closed system that prevents any unwanted organisms to populate it. Unwanted inhabitants are a hazard of buying live rock from the ocean. You never know exactly what you are going to get in terms of hitchhikers and whether they will be friendly or harmful to your fish. These hitchhikers will need to be manually removed during the curing process once home and in the tank.