How to Choose Live Rock for Your Saltwater Aquarium

Live rock is an essential component to your new saltwater aquarium. While you can seed dry rock to perform the same function, live rock is typically filled with far more of the bacteria and organisms your saltwater aquarium requires to be properly set up and become a healthy environment for your fish and other aquatic life. There are upsides and downsides to live rock, however. The upside is that the rock is already seeded with organisms from an established saltwater aquarium. The downside, on the other hand, is that live rock often includes "riders," or small parasites and harmful bacteria, as well as less-desirable invertebrates. In addition to this, live rock typically costs far more than inert rock, particularly if the shop selling the rock took the pains to remove any harmful organisms from the rock before offering it for sale.

Live rock in the aquarium is used primarily not as a decoration, though that is an added benefit, but rather it helps carry out the nitrification process. This is particularly true of live rock that appears to be extremely porous. All of the pores and fissures in the surface of the rock serve as dwelling places for the previously mentioned bacteria. These bacteria are what break down the harmful organic compounds in your aquarium and turn them into compounds that the fish and other creatures in your aquarium can use. For the most part, live rock is actually a piece of coral rubble sourced from areas where there are large concentrations of coral reefs such as areas of the Caribbean, Fiji and the Philippines. These pieces of coral rubble are not lab created, though you can conceivably seed porous man-made stones to serve the same purpose. Due to regulations regarding the collection of live rock from natural habitats, it has become increasingly common to see live rock that is aquacultured rather than harvested from the wild.

When you select a piece of live rock for your aquarium, take into consideration the overall size of the aquarium as well as the amount of water that the live rock will displace. If you select a particularly large rock for a smaller tank, for instance, you may find that your rock will displace as much as 1/3 of the water in the tank. This will effectively reduce the amount of water available for your fish and invertebrates. Instead, plan to purchase enough rock to make up between approximately 10% and 25% of the overall volume of the water based on the size of the rock, but not taking into account the porosity of the live rock or any of its fissures.

Look for cured live rock whenever possible. Cured live rock is rock that has been collected, and then subjected to treatments designed to kill off the weaker bacteria and organisms on the rock, leaving behind the stronger, which will then have room to colonize on the rock without having to vie for space with the weaker organisms. Because this process can take several weeks, it is best to purchase this cured live rock for your tank rather than uncured.

In a decorative sense, there are a variety of types of live rock, and many of them display very different characteristics. Some look like fossilized plants and sea life. Others more resemble what we commonly think of as rock. After you have made your selection, you have approximately 12 hours to install the live rock in your aquarium, depending on how the live rock is packaged. Usually, you will be provided with a Styrofoam cooler that you can transport the rock in, but it should be placed in your tank as soon as possible.

While live rock may be slightly more expensive than typical inert rock, it will provide a much easier and quicker way to set up your saltwater aquarium, regardless of your present skill level.

"The Saltwater Aquarium Handbook"; George Blasiola; 2010