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When Is Live Rock, Live?

A Frequently Asked Question

By Stan & Debbie Hauter, About.com

Having the opportunity to work in the fish department at the Animal Jungle Pet Store in Kinston, NC has given rise to many interesting questions from customers that want to start a saltwater aquarium. A particular question that we hear often is, when is live rock, well, live, which is a very good one.

Read the following statements and see if you agree or disagree on these points about live rock, then participate in the poll we have included at the end of this discussion to let us know what you think.

  • It is a misconception that the rock itself is alive. What makes it live are the many forms of micro and macro marine organisms that live on and inside of it. Rocks, coral rubble, and other pieces of natural reef based materials are only made up of the calcium carbonate skeletons of long dead corals and other calcareous organisms.
  • Dried pieces of rock are not alive if they have not been kept in saltwater.
  • When you put dried pieces of rock into a saltwater aquarium they become live, but not immediately. It takes time for beneficial bacteria to populate it and marine organisms to begin growing on it.
  • When you transport or ship rock that has been kept or cured in a saltwater system to a new location, as long as it has been moved or shipped properly it is still alive when you place it into another aquarium.
  • Live rock is ONLY considered to be such when the growth of marine life such as coraline algae, micro and macroalga, sponges, tube worms, and/or other types of sessile invertebrates are "visibly" present.
  • This is the most debated question, and one that we ourselves discuss often. Like many aquarists, Stan says YES, rock is only live when things can be seen growing on it. I say NO, with reasoning being that just because you cannot SEE something growing doesn't mean it isn't there. Aquarists like myself perceive that as soon as microscopic nitrifying bacteria starts to grow on any rock, because these unseen organisms ARE living entities, at this point it becomes "live".

What do you think?

Stan & Debbie Hauter
Guides since 1997

Stan & Debbie Hauter
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