Reef Aquarium Rock Explained, Part 1

[R2R Articles]

Seawitch submitted a new Article:

Reef Aquarium Rock Explained, Part 1

Or, What Kind of Rock Can I Put in My Saltwater Tank?
In the broadest of terms, there are basically two types of rock for saltwater aquariums: live rock and dead rock. So, we're going to look at them one at a time, and try to explain the differences for the benefit of beginners.

Live rock from the ocean. There's bubble algae on it in the middle (a nuisance).

Photo is from the Reef2Reef archives, ©2018, All Rights Reserved

Live Rock:

Live rock is either A) wild rock that has either been plucked from the ocean or B) some other kind of rock, natural or artificial, that has been placed in the ocean (farmed) specifically for the purpose of making it live or C) some kind of natural or artificial rock that has been aquacultured on land with the appropriate organisms to make it "live". So, B) and C) above are the sustainable alternatives to wild-harvesting, and the only way to avoid damaging a living reef.

While live rock, for the most part, is a combination of dead pieces of coral, calcium carbonate, and other ocean material, it is also populated more or less with beneficial bacteria that serves as a chemical filter for saltwater aquarium water. This type of rock typically comes with other saltwater organisms attached both good ones and bad ones. What and how much arrives on or with your live rock depends on where it comes from and how well it has been shipped. If it has been in the ocean recently, it might have sponges, corals, tiny invertebrates, crabs, coralline algae, worms, feather dusters, and/or other forms of life.

Live rock is the foundation of both our ocean coral reefs and home reef aquariums.

Live artificial rock aquacultured in the ocean.

Photo is from the Reef2Reef archives, ©2018, All Rights Reserved

While live rock is not an aquarium requirement, reef aquarists generally choose to use at least some of it for the pleasing aesthetic it brings to a tank (live rocks are often vibrant purple, green, or red), on principle to create an environment for the inhabitants as close to the real one as is possible in a glass box, as well as the practical benefits of providing shelter and nitrification. Waste from old food, poop, or decaying organisms increases ammonia levels. Live rocks are typically already colonized with bacteria that help convert waste into less harmful compounds, and depending on the condition of the rock, more bacteria will develop inside it and on it over time. Live rock eventually becomes a major part the aquarium filter.

Most of the live rock you’ll find online or at a local fish store is harvested from a living coral reef. In some areas, live rock is harvested using dynamite or crowbars. Because this is such a destructive practice, many nations have banned this type of harvesting, although live rock can also be collected in shallow ocean water where small pieces of coral wash up after being detached from the reef due to storms or other damage, assuming it's legal in whatever area that is.

Live rock from the ocean can be reef rock, inshore reef rock, and reef rock from darker areas of a reef system that may have much less life on them. Depending on where the rock comes from, the life forms on it may be slightly different.

At the time of this writing, according to Mike Paletta, "the collection of ornamental fish in Hawaii is BANNED. The collection and sale of live rock and coral from Fiji: BANNED. The permits for shipping coral, anemones and live rock from Indonesia: HALTED."

Much of the available (wild) live rock comes from the Caribbean and the South Pacific and each type, typically named for the area it’s from, has its own unique qualities. Some live rock is dense, and some is very lightweight and porous. And artificial live rock may have an altogether different density or porosity. That's why the rule of thumb of 2 pounds of live rock per gallon of tank water is not a hard and fast rule. Furthermore, live rock is expensive.

Sites like Saltwater Aquarium Blog and ReefHacks suggest setting up your tank with dry or dead rock and adding in 10 to 20 pounds of live rock once you’re happy with how it looks. Dry rock is less expensive than live rock, doesn’t have any hitchhikers, and will, over time, become colonized by coralline algae, bacteria, and invertebrates from the live rock you add to your tank.

Live rock is chosen for its look so it’s best to purchase it in person at a local fish store. This isn’t always possible so here are a few online places to find live rock.


● Fishy Business Aquatics

● World Wide Corals

● LiveAquaria

● Amazon


Make sure to read the reviews, check that they ship to your country, and ask the helpful aquarists in the Reef2Reef forums for advice.

No matter where you get your live rock, if organisms on the live rock die off during harvesting and transportation (and they will) they pose a risk to your aquarium. These rocks require curing before installation in order to remove the dead and decaying material. Curing is a topic that we will explore in depth in a future article.

How to tell if your live rock needs curing:

● Smell the rock to see if it stinks of rotten fish. If so, it needs curing.

● Place the rock in a container of saltwater (that is the appropriate temperature and with a filter or powerhead to move the water around) for a day and then test for ammonia. If there’s ammonia, your rock needs curing.

Dry Rock Sometimes Referred to as Dry Live Rock

Dry live rock is not exactly alive but it's not exactly dead either, so I'm grouping it with live rock. Remember the movie, "The Princess Bride?" "It just so happens that your friend here is only MOSTLY dead. There's a big difference between mostly dead and all dead. Mostly dead is slightly alive."

Dry live rock is rock that used to be alive, but hasn't been alive for a while. So, either this rock has been out of water or it has been in a dead tank with no obvious signs of life. Now, if it's been sitting in the sun for 10 years, then it's probably completely dead, but if the rock has only been out of water for a few weeks or months, then it may still have some life in it, even if it's only spores waiting for the right conditions to come alive again.

If it stinks with a crash, then it has some decaying matter in it or on it. In any case, no matter how alive or how dead it is, it has to be cured. And curing dry live rock is slightly different than curing live rock.

Dry live rock may be slightly alive or totally dead, but its benefit over live rock is twofold: dry live rock is cheaper than live rock, and it's very unlikely to contain any bad hitchhikers.

Dry live rock also has a downside. If it contains hardly any or no life, then it might as well be dead, because it will take as long as dead rock to revive under the right conditions. It can be more difficult to cure, and it's highly unlikely to have any good hitchhikers either.

If you're not sure if your rock is alive or dead, find out where the source was. If the rock came from an inland quarry, it's dead no matter what it's called or branded. If it hasn't been alive in 1000 years, then it's dead. Similarly, if it was recently alive but has been sterilized, and is guaranteed not to have anything bad on it, then it is also not going to have anything good on it either. That's called dead rock.

In Part 2, we'll talk about dead rock. And by that we mean totally, thoroughly, and completely dead.

A very pretty small rock aquascape.

Photo from the Reef2Reef archives, Travis Stewart © 2018, All Rights Reserved

Additional resources:

● Buying Live Rocks for Your Marine Aquarium

● How Much Live Rock Do I Need?

● How to Cure Live Rock

● Live Rock (Wikipedia)

● https://www.practicalfishkeeping.co.uk/features/articles/how-to-make-your-own-live-rock

● http://www.tfhmagazine.com/saltwate.../creating-your-own-live-rock-full-article.htm

● https://www.reef2reef.com/threads/banned-but-is-there-still-hope.403782/

● https://www.law.cornell.edu/cfr/text/50/622.225

About the Author: Robyn Roste

With more than 10 years of experience in writing, marketing, and audio editing, Robyn Roste’s experience combines new media, broadcast media, journalism, public relations, and social media. She has a Bachelor of Journalism and loves learning new things and helping people understand complex subjects. Robyn recently won a prize from the Professional Writers Association of Canada (PWAC) and was shortlisted for a Literary Arts Award in British Columbia.

Now living in British Columbia, Canada’s beautiful Fraser Valley, Robyn enjoys rural living even if it means running into the occasional wild animal. When there’s spare time, Robyn and her husband travel to places where they can snorkel and see the fish from The Blue Planet for themselves.

 

[Daniel@R2R]

Robyn, thanks for another excellent article! This is a very helpful explanation for beginning hobbyists learning about live rock. I love that more and more companies are coming about that are focused on culturing live rock or even creating synthetic forms of rock that can be used in an aquarium to avoid harvesting live rock directly from our reefs. Thanks again for your article, and keep that great content coming!! Looking forward to Part 2!!

 

[ca1ore]

I do so miss that fresh direct-from-the-ocean rock, with all its attendant aromas.

 

[andrewkw]

I do so miss that fresh direct-from-the-ocean rock, with all its attendant aromas.

I'll never forget when I went to start my first 15g nano in 2005. I went to a brand new reef store which sold nothing but 1000s of lbs of haitian lettuce rock. The entire store was just full of live rock in every vat. It's funny how hitchhikers have gone from good to bad over the years. I'm not saying there aren't quite a few bad ones, but there are probably even more good ones.

 

[Stigigemla]

It is very sad to see that the author missed one of the important things with live rock. It is not only colonized with bacteria but also with diverse small animals as worms, copepods, amphipods and others.
They do a good job in rinsing the stone so it is not clogged with detritus. We have some reefers here having their tanks with dry rock crashed after a year or so and the main reason for that i believe is the lacking of animals rinsing the rock.
Another function of these animals is being food for fishes like mandarins and other that feed from rock surface.

 

[PedroYoung]

Pics of some of the last true live rock out of Fiji. Got one of the last airfreight shipments in late January of last yr. Still in my 100G stock tank waiting to be installed in my new 200G tank (I am slooooooooow). Came in with lots of coraline, some inverts, really beautiful stuff. The fluorescent lighting in my basement doesn't really do it justice.

image by Peter Young, on Flickr

image by Peter Young, on Flickr

image by Peter Young, on Flickr

image by Peter Young, on Flickr

 

[Travis Stewart]

Great read, thanks for the picture shoutout!

 

[Bouncingsoul39]

This "article" is a train wreck written by someone who clearly has zero experience in the hobby. It is full of misinformation and very misleading. Why is the picture of ocean live rock used one that is covered in nuisance algae and looks terrible? It's like the worst possible example you could use and not at all like what you would get from Tampa Bay live rock or their peers. If this is what hobby beginners will be using to educate themselves, this hobby is in a very very sad state.
Ah, remember the good old days when articles were written by hobby experts? This hobby has been around for over 30 years, ya know? This article should be deleted from the site.

 

[._Z_.]

This "article" is a train wreck written by someone who clearly has zero experience in the hobby. It is full of misinformation and very misleading. Why is the picture of ocean live rock used one that is covered in nuisance algae and looks terrible? It's like the worst possible example you could use and not at all like what you would get from Tampa Bay live rock or their peers. If this is what hobby beginners will be using to educate themselves, this hobby is in a very very sad state.
Ah, remember the good old days when articles were written by hobby experts? This hobby has been around for over 30 years, ya know? This article should be deleted from the site.

Can you cite the other pieces of “misinformation” so that the author, and any new reefers reading this can learn from your expertise?

 

[Bouncingsoul39]

Can you cite the other pieces of “misinformation” so that the author, and any new reefers reading this can learn from your expertise?

We can start with the part about live rock being collected by crow bar and dynamite. Lets see some fact based evidence of that zinger.

 

[VR28man]

Robyn, thank you for the effort in writing this article. I would not put it the way @Bouncingsoul39 did, but I do take issue with the statement

Most of the live rock you’ll find online or at a local fish store is harvested from a living coral reef.

Very little "live rock" available these days online in the US is collected from a wild reef, because of the bans mentioned above.

Also, aquacultured rock (originating in Florida, at least for the US market) is far more available now (Again in the US) than wild rock. Recommended vendors include Tampa Bay Saltwater (@liverock ), KP aquatics, and several others.

As far as

In some areas, live rock is harvested using dynamite or crowbars.

those are the same places (not necessarily countries! just portions of certain countries) where fish are caught with explosives (for local consumption) or cyanide (for live export for the aquarium or exotic seafood industry*). Of course, places that collect like that should be shunned by the distributor. This is a reminder to be investigate where you get your livestock from, as possible.

* IIRC, the live export of fish for exotic seafood use is a bigger industry than for the aquarium industry. Granted that there's almost no species overlap.