Live Rock is a term that doesn't imply that the rock is living, but rather covered and inhabited by living things. When you first start an aquarium with purified water, there are no living things in it. To rectify this situation, you can purchase "live rock" through local pet stores and online dealers that can be placed in your aquarium.
What sort of critters are found in live rock? The most important ones are bacteria, which will filter out nasty toxins like ammonia and nitrites that are harmful to fish. There are also small protozoans and larger multi-cellular creatures like copepods and algae that serve as food for certain fish. Some live rock can include large creatures like crabs, shrimp, anemones, coral, and even octopus. All of these creatures will help create a balanced ecosystem that mirrors those found in the ocean.
Live rock can be found in any part of the ocean, however it should be noted that harvesting it without a license is illegal in many parts of the world, including the United States. It should also be noted that harvesting your own rock near the shore can be a mistake since shoreline waters are often polluted and the water can ruin your aquarium. Licensed live rock dealers often "seed" the ocean with dead rock and they harvest it as live rock after it is taken over by creatures.
Purchasing live rock is no doubt expensive, with many dealers offering it for $2-6 per pound. If you buy online, you have to pay shipping costs that are typically around $1 or more per pound. The drawback to buying online is that you will have more "die off" or more organisms that don't survive the trip to your house. If you purchase live rock from a local store, the vast majority of the organisms will survive, but it will probably also cost more.
After you purchase live rock, you need to "cure" it by clearing it of dead organisms. If you purchased it from a local store, it might not need to be cured, but rock ordered online will most certainly need to be cured. If you are intending to add the rock to an aquarium that is already inhabited by fish or other creatures, you will have to cure the rock in a separate container or aquarium to avoid harming the fish. Curing can be accomplished by simply placing the rock in saltwater and letting it sit for up to 6 weeks, by which time the decomposing matter should be digested by the bacteria.
Sometimes live rock is inhabited by nasty critters that can chew on coral or even kill fish. To prevent these creatures from getting into your aquarium, you can dip the live rock in high salinity water or freshwater. After dipping, the organisms will likely flee the rock and enter the water, where they can be sorted and you can add what you want to the aquarium. Mantis shrimp and certain crabs are the most frequent aquarium pests, so be on the lookout for these particularly.
After curing your live rock, you can add it to your aquarium (unless you were curing it in the aquarium). You should try to stack the rock in a manner that creates "caves" for the fish and invertebrates to hide in. At the same time, you should try to maximize the surface area of the rock that is exposed to the water and allow flow from powerheads through the rocks. Finally, make sure that the rocks are stable and will not easily be knocked over, potentially crushing fish or breaking glass.
How much live rock do you need? Most aquarists agree that 1.25 to 1.75 pounds per gallon of water is a good ratio. This amount of rock will carry sufficient bacteria to filter the waste of any fish that you place in the aquarium. You can always add more live rock in a refugium or sump, but it is not necessary.
Live rock isn't the only filtration you need. The Berlin method of filtration (arguably the most popular used by modern saltwater aquariums) calls for the usage of live rock and a good protein skimmer to maintain water quality. Live rock is expensive, but it will save you a lot of money in the long run since you won't need to buy replacement filters for canister filters and other water cleaning devices.
Return to the Aquariums Section
Other Articles That You May Be Interested In: