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Ultimate Guide to Live Rock in Reef Aquariums

Table of Contents

Live rock plays an essential part in any saltwater aquarium. 

Without it, there would be very little surface area for beneficial bacteria to live, less hiding places for fish, and make it much more difficult for corals to attach places.

Given enough time, all rock placed into aquariums can become “Live Rock”, that being said, when starting an aquarium, you have the choice of doing so using live rock or dry rock. 

This article will cover:

  • Explaining what live rock is
  • starting an aquarium with live rock
  • advantages of live rock
  • disadvantages of live rock
  • types of live rock
  • environmental impact of live rock
  • And More!

What is Live Rock?

Live rock refers to rock that has built up “life”, in the form of:

  • Bacteria
  • Coraline Algae
  • Other micro-organisms.


While a majority of the life on live rock is microscopic, it plays a huge role in any aquarium.

Live Rock

Benefits of Live Rock

As far as the advantages of live rock goes, these will pretty much be the opposite of the disadvantages of dry rock.

The first advantage of using live rock is that it will massively decrease the amount of time it takes to cycle your tank, given the massive amounts of beneficial bacteria and bio diversity it will come with.

Disadvantages of Live Rock

The first disadvantage that we can think of when it comes to live rock, is that it’s much more expensive than dry rock.

The second disadvantage of live rock is that it’s not as flexible with it’s formations. Typically the shape it comes in is the shape you’ll get, unless you do some smashing. It’s a lot easier to do your aquascaping on land than it is arching your arm into your tank.

A third disadvantage that we stated in the advantages of dry rock section, is that it’s not the most sustainable practice when harvested from the oceans.

Lastly, one of the most commonly complained issues with live rock is that it comes with reef hitchhikers. While there’s certainly beneficial hitchhikers life copepods, some startfish, and sponges, there are also some REALLY annoying pests that can come with it, like aptasia, fireworms, mantis shrimp, and more.

If you’re smart with where you get your live rock from, this can be an advantage, but be sure to account for this when starting your tank.

We would NOT reccomend getting live rock from your local fish stores community live rock area. This is a sure fire way to get a mystery box of reef pests and hitchhikers.


One of the most important benefits of introducing live rock into a saltwater aquarium, is that it gives a boost to the biodiversity of the aquarium.

As aquarists, we are attempting to take a portion of nature and place it into our homes. Recreating nature exactly is near impossible, and requires us thinking about every detail, including microscopic bio diversity.

Types of Live Rock

Fiji Live Rock

The most common type of live rock these days is Fiji live rock.

As you can probably guess, this rock comes from Fiji or other areas in the Indo-Pacific.

It’s often very white on first glance, but will quickly turn a variety of colors once introduced into an aquarium.

Fiji rock is great considering how porous it is, maximizing the surface area for beneficial bacteria to live on.

fiji live rock example

Considering that this rock needed to be pulled out from the ocean (often times using destructive methods), shipped to your area via expedited shipping, while keeping it in stable parameters to limit die off, and giving the distributor a profit margin, typically causes Fiji live roc to be rather expensive.

Aquacultured Live Rock

The next type of live rock you’ll encounter is aquacultured live rock.

This is can be any rock (whether man made or once naturally occurring rock) that is placed into a natural environment or simulated natural enviroment to encourage the development of you guessed it, beneficial bacteria.

This is generally the most accepted and sustainable practice for aquarists to practice, given that it doesn’t take anything out of the oceans.

Aquacultured Live Rock

Enviromental Impact of Live Rock Collection

Given the severe sustainability issues that come with live rock extraction, the practice has been banned from many placed in the world, like the United States and a lot of the Caribbean.

Some other countries have placed regulations on the practice but still allow it, like Australia and Fiji.

Curing Live Rock

Live Rock and Reef Hitchhikers

Aiptasia, one of the most frustrating hitchhikers in the hobby.

Reef hitchhikers are one of the most frustrating but entertaining part of the hobby.

If you’re in any reefing groups, you’ll always get a good laugh out of people posting some mystery creature while the comments try and ID the pest.

Some of the most common 


Dry Rock vs Live Rock

There is a pretty big divide in the reefing community about whether you should use live rock or dry rock inside your tanks. Each method has pros and cons which we aim to tackle here, so you can make the best decision for your needs. Considering we already talk about live rock and it’s benefits in this article, we’ll quickly cover the advantages and disavtantages of dry rock.

Advantages of Dry Rock

Dry rock in my opinion, the best option for patient and calculated reef keepers.

The first advantage of dry rock is that it’s cheaper to buy and transport than live rock. If you’re entering the hobby on a budget, then this should not be underlooked.

You will have to account for the extra cost of a quick start product, but this is usually a marginal cost increase.

The second advantage of dry rock is that it’s much easier to create amazing aquascapes with. Whether you’re glueing together a variety of dry rock pieces to create your dream design, or purchasing an existing formation, you have that extra flexibility with dry rock. In most cases, live rock comes in the shape it’s going to be.

The last advantage of dry rock that we can think of, is that it’s much more of a sustainable route for the industry. There is only so much live rock that can be taken from oceans without harm. On top of that, the practices for live rock extraction are typically not great for the environment.

Disadvantages of Dry Rock

The first disadvantage of dry rock, is that it’s going to take longer to cycle your fish tanks using dry rock. This is due to your rock containing no beneficial bacterias already. Using quick cycle products, you can expedite this process, but it will always take longer to cycle a tank using dry rock. In terms of time difference, we’re likely talking a matter of a few weeks. 

The second disadvantage of dry rock that sort of ties into the first point, is the severe lack of biodiversity that dry rock has. Even if you try to mimic this process with quick start solutions, there are some things in nature you just can’t replicate.

Frequently Asked Questions

The most common rule is to include 1-1.5 pounds of live rock per gallon.

This is a rule of thumb, and heavily depends on factors such as:

  • How much you plan to stock your tank
  • What other forms of biological filtration will you use
  • Presence of a sand bed
  • Feeding habits
  • and more!

Please feel free to leave a comment if you have any questions on how much live rock to include inside your aquarium.

If you decide to purchase your live rock at a fish store, you’ll often find a scale there to help measure.


This isn’t neccesarily the most common practice, but can be a great middle ground that allows you to get the best of both worlds.

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Concluding Thoughts

Now that you have an idea about what using live rock in an aquarium entails, you should be better equipped to make the decision on what type of rock you’ll use in your tank.


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    My name’s Austin, and I created OtterAquatics to teach aquarists of all skill levels on how to succeed in the hobby.