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Curing Live Rock for Your Aquarium


saltwater aquarium containing live rock

What is Live Rock?

If you are new to saltwater fish keeping you may be wondering what live rock is. The rock itself isn't alive, but it contains many small reef inhabitants that are, such as algae, corals, sponges, and many other types of invertebrates.

Purpose of Aquarium Live Rock


The most important function of live rock in a marine aquarium is that it functions as a biological filter. Live rock is able to serve this function because it is colonized by bacteria that feed on waste products produced by the fish in the tank. The bacteria on the live rock break down waste products that are produced by aquarium fish, such as ammonia, into substances that aren't harmful to the fish. Using live rock in your saltwater aquarium will greatly enhance the survival rate and health of your fish.

Another benefit of using live rock in your aquarium is that it provides a variety of marine life forms, such as marine algae and invertebrates for your fish to graze on. In their natural habitat, marine fish spend most of their time in search of food. Providing well-established live rock in your tank will enable your marine fish to feed throughout the day.

In addition, many saltwater fish are not captive bred and were removed from their natural habitat before arriving at the dealer where you obtained the fish. Providing live rock in their tank will help them to acclimate to life in captivity because most of these fish will be used to feeding off of rocks similar to what you'll have in your aquarium. In fact, some fish don't survive long in captivity without feeding on the reef invertebrates and algae that grow on live rock.

Another very important purpose of having live rock in your aquarium is that it provides hiding places for many marine invertebrates and animals.

You can arrange the rock work in your tanks to provide caves and hiding places so that your fish will feel more secure. A fish that feels more secure and safe will be less prone to disease.

Uncured versus Cured Live Rock

You can buy uncured rock or cured rock. Cured live rock is free of dead or dying organic matter, whereas uncured live rock may have dead or dying reef organisms attached to it. If you buy uncured live rock you will need to clean it yourself. Don't place uncured live rock into an aquarium that has fish or other life forms living in it. It is likely to have dead sponges, crustaceans, and other dying organisms that will pollute the tank water. Cured live rock is more expensive, but it is worth the added expense.

Curing Live Rock

If you buy uncured live rock you will have to cure it yourself. You do this by cleaning off all of the visible debris (keep it moist during this time) and then you place the uncured live rock into a saltwater filled container (not your aquarium). You must mix up the saltwater the same as if you were using it in your aquarium. You need to place a heater in the container with the live rock set to about 80°F (27°C) and you will need to use a powerhead to aerate the water and to get the water moving.

The water containing the uncured live rock is likely to have a very foul odor because of the dead or dying reef organisms on it.

You will need to keep changing the water in the container of live rock for 2-3 weeks or until the water no longer smells bad. Before adding the live rock to your aquarium do an ammonia and nitrite test on the water in the live rock container and make sure they both read zero before adding the live rock to your main aquarium.

The following is an excellent video from You Tube that provides a great demonstration on curing live rock.