Live rock is a very interesting and beneficial addition to your saltwater aquarium. Live rocks are pieces of coral reef which have been broken off by nature. This often occurs during a hurricane or a tropical storm. The reason for the name “live rock” is because it contains living creatures. Small crabs, worms, anemones, and plant growth can be found originating from pieces of live rock. I once had the wonderful surprise of discovering hundreds of baby starfish emerging from a batch of live rock added to my saltwater aquarium!

In addition to providing forms of life for your saltwater aquarium, live rock also acts as a natural biological filter. The large surface area and numerous holes provide conditions which are ideal for both aerobic and anaerobic bacteria to thrive in your tank. These aerobic bacteria help to convert harmful substances produced by fish and uneaten food, such as ammonia, into nitrites and then into nitrates. Anaerobic bacteria convert the nitrates into a gas that rises to the surface and leaves the tank. This is not a substitute for regular water testing, however; it is just an added benefit.

Live rock can also supply natural homes and hiding spaces for the fish and other organisms in your saltwater tank. Some types of algae found in live rock can be beautiful shades of pink, purple, and yellow, adding to the beauty of your tank and providing food sources for its inhabitants. Observing the rock to see what emerges is a very enjoyable and relaxing experience. Sometimes it is even more interesting than watching the fish you have purchased.

Two main types of live rock are available. They are known as cured rock and uncured rock. Uncured live rock is cheaper than cured rock, but you aren’t likely to see as much life succeed in this rock type unless you cure it yourself. The process of curing consists of scrubbing the surface of the rock to remove debris and dead life forms. If your saltwater tank does not have any fish or other creatures added yet, the rock can be placed into the tank to cure. Otherwise, you will need a container for curing it. Aged, pre-mixed saltwater is available to help this process.

Cured live rock has already been scrubbed and placed in a tank for curing for several weeks to several months before it is purchased. Though it is more expensive, you will be saved the trouble of having to buy additional materials, and will not have to work or wait to cure it yourself.

Other types of live rock are Base, Pacific, Atlantic, Gulf, Caribbean, and Aqua cultured rock. All but aqua cultured rock comes from natural oceanic areas. Base rock is the cheapest, Pacific is the most porous, and Atlantic, Gulf, and Caribbean are the least porous. Aqua cultured rock is an artificial type of live rock, created by submerging a porous rock into the ocean for several years. This allows the buildup of the beneficial bacteria and organisms, and is a very environmentally-friendly choice as you can be sure no coral reef was purposely broken off.