How to Choose Reef Aquarium Rock

How to Choose Reef Aquarium Rock

Reef aquarium rock is the foundation for every successful reef tank. Rock is not just the physical foundation of the system but also the biological foundation that plays an essential role in the aquarium’s filtration.

What is Reef Aquarium Rock

Reef aquarium rock comes in various sizes and shapes and can be made from the skeletons of old coral reefs, concrete, and even synthetic substances. The two main types of reef aquarium rock are live rock and dry rock.

Why is Reef Aquarium Rock Important?

Rock plays an integral role in creating a successful saltwater tank in the following ways.

  1. Foundation of a Reef Tank: Reef aquarium rock is the physical foundation of the aquarium.
  2. Habitat for Marine Life: Aquarium rock is the home to most of the marine life in the tank, providing them with shade, food, and a place to hide. It also provides space to mount corals.
  3. Biological Filter: The rock provides plenty of surface area for beneficial bacteria to populate and aid in biological filtration.
  4. Helps Maintain pH: Most reef aquarium rock varieties also help keep the pH level elevated, which improves coral health and growth.
Aquarium Aquascape: Why Reef Aquarium Rock is Important
Aquarium Aquascape

Types of Reef Aquarium Rock

As the aquarium hobby has continued to advance, more rock options have become available. We will explain each of the main options below and their benefits and drawbacks.

Live Rock

Live rock was the original hardscaping rock of choice for most reefers, and it is still the best way to cycle your aquarium quickly and get it packed with beneficial bacteria. Most live rock tends to be harvested from a traditional reef or aquacultured with pieces of rock that initially originated from a wild reef.


  • It contains large amounts of beneficial bacteria that aid in filtration
  • Allows you to cycle your tank faster than other alternatives
  • Established live rock will have the attractive purple coralline algae that most reefers love


  • Generally the most expensive option
  • Risk introducing undesirable pests or hitchhikers into the tank
  • It May not be sourced ethically
Live Rock with Coralline Algae: Types of Reef Aquarium Rock
Live Rock with Coralline Algae

Dry Rock

Dry rock is the usual choice for those who want a cost-effective way to hardscape their systems. Most dry rock is mined from the ground and was initially live rock hundreds of years ago. Dry rock must go through a curing process before being added to your system.


  • Most affordable option for a reef or fish-only tank
  • Generally free of all pests
  • It comes in a variety of shapes and sizes


  • Must be cured before being added to the tank
  • It takes time to develop beneficial bacteria and coralline algae
Reef Aquarium Rock: Dry Rock Courtesy of Marco Rocks
Dry Rock Courtesy of Marco Rocks

Artificial Rock

Artificial rock is the newest option in the aquarium-keeping market. This rock is manufactured; however, it looks realistic compared to live rock options. CaribSea, Real Reef Solutions, and Reef Rax all offer different forms of artificial rock in multiple colors. Some of these options contain dormant spore bacteria to help the cycling process.


  • Generally free of pests
  • Most sustainable alternative
  • Come in unique shapes, styles, and colors


  • It can look slightly artificial
  • It takes longer to cycle than live rock

Comparison Chart

Type of RockLive RockDry RockArtificial Rock
Already established live rock will require minimal maintenance

Dry rock will grow a lot of algae as it transitions into live rock

Artificial rock will also grow algae as it turns into live rock
Ease of Cycle
Will help cycle the tank the fastest

Will cycle the tank the slowest

Will cycle slowly unless the rock contains dormant spore bacteria
Hitchhikers/ Pests
Can contain hitchhikers

Will not contain hitchhikers

Will not contain hitchhikers
Filtration Capability
Provides biological filtration immediately

Need time to grow beneficial bacteria to aid in filtration

Need time to grow beneficial bacteria to aid in filtration
Rock ShapeUsually comes in base rock formAvailable in base rock, shelf rock, and branch rockAvailable in base rock, shelf rock, and branch rock
Rock ColorColor VariesUsually very light beigeComes in beige and Coraline color
Ideal ForPerfect for those who want to quickly cycle their aquarium and add corals and fish almost immediately.Perfect for those who want to start from absolute scratch and wish to prevent any potential hitchhikers from entering the tank.Artificial rock is ideal for those who want to start from scratch but want unique shapes, sizes, and color options.
Reef Aquarium Rock Comparison Chart2

How Much do I Need?

The amount of rock required will depend upon a couple of factors; (1) the planned aquascape and (2) the type and density of the rock. Rock with more surface area tends to be lighter than base rock. Use approximately 1/lb per gallon for a minimalist aquascape and 2/lb for a densely packed scape as a general rule of thumb.


When it comes to the prices of different reef aquarium rock, they vary significantly depending on numerous factors. Please consult the comparison chart below to get an idea of what you can expect to pay per pound of each rock variety.

Type of RockLive RockDry RockArtificial Rock
Price Per Pound$8-$16 per pound$2-$6 per pound$5-$12 per pound
Reef Aquarium Rock Budget Comparison Chart

Buying the proper rock for your reef tank will ensure that your system has the appropriate foundation to build upon for years to come. If you have any additional questions about choosing the proper reef aquarium rock, our support team would be happy to assist you.

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