Live rocks are made of calcium carbonate skeletons of long dead corals and other calcerous organisms. There are several types of live rocks. Reef rocks are coral pieces covered of algae and sponges. In-shore rocks are inside reef rocks covered with macroalgae, clams, mussels, crabs and shrimps. Dead base rock serve as reef system base because it has no live growth.



The two main types of live rocks are cured rocks and uncured rocks. Cured rocks are free of dying organic matter. Usually they have been inside the retailer's tank for a longer period of time. They are more expensive because they are higher in quality.

Uncured rocks are rocks that may acquire non living or dying reef organic matter attached to it. There is a possibility of higher die off rate. They are generally cheaper.

Some live rocks are classified according to origin. Pacific rocks are more porous rocks from Fiji, Marshall Islands, Indonesia and other Pacific areas. They have more carves, nooks and holes. Fiji is usually lighter and has light pink color. Tonga rocks are heavier and elongated. Most popular tonga rocks are the slab ones. Marshall and Kaelini rocks are even lighter then Fiji rocks. Walt Smith rocks are beautiful and covered with coralline algae. Caribbean rocks have green, pink and purple colors. They are usually with larger holes. Melanesian rocks have red, orange, yellow, green, pink and purple colors. They are flattish in appearance. Nano rocks come from Indonesia with different shapes. They are often used in smaller aquariums. They are the best filter live rock which makes them the most expensive.

Atlantic Rock and Gulf Rock are not as porous as the ones mentioned above. They are not recommended to be used as the main type of live rock for the aquarium.

Live rocks are the main biological nitrification base or bio filter of saltwater aquarium. They serve as a hiding, living space and food source for saltwater fish and invertebrate. The pink and purple coralline algae also serve as attraction.

Live rocks also make the aquarium look more natural. This natural-feel is essential for the health and comfort of reef fish.

When buying live rock for saltwater aquariums, it is recommended that the weight is 1.5 to 2 pounds per gallon. For instance a 30 gallon of water must have 45 to 60 pounds of live rock.

Start with high quality live rock just like ones that are highly encrusted in coralline algae. If on a budget, then it can also be a combination of a cheaper base rock and more expensive live rock.

Avoid those with hair algae. Maintain low nitrate and phosphate levels. It is better to set up the tank first before buying live rocks and ensure they are stacked in a stable manner.

Avoid overloading the system. Also avoid stacking rock solids together. Live rocks need protein skimmer and lighting. Inspect rocks and smell them. Avoid unwanted pests and foul odors.

Identify the length of time it has been cured and the geographic location of its origin. If rocks are shipped, remember that longer shipping time increases chances of die off.

Fresh, unseeded and uncured rocks are the same.