This article provides a brief introduction to reef aquariums. It will first provide an overview of the reef aquarium along with a short history. Then we'll discuss how reef aquariums fit into the larger category of saltwater aquariums. After that we'll go into more detail about what you might find in a reef aquarium. A lively discussion of pros and cons for keeping a reef aquarium follows that. Finally, we'll conclude this article with online reef references for you.
Overview of a Reef Aquarium
In its most basic form, the reef aquarium is a tank full of invertebrates such as corals, anemones, and other neat creatures. Instead of the fish being the focus, the focus of the tank is on the reef itself.
Saltwater aquarium hit it big around the 1950s due to advances in filtration systems over anything else. That and the commercial success of air transportation to help move saltwater fish from the wild to your local fish store. But actually focusing on the reef as opposed to the reef fish is a much newer explosion in the fish hobby world. The advent of the Internet over the past 10 years has really helped disseminate information to reef hobbyists around the globe.
FO, FOWLR, and Reef
Reef Aquariums are saltwater aquariums where the focus is on invertebrates that you'd find on a reef. The focus isn't on the fish the way they are in a FO or FOWLR tank. FO what?!?! Here we go:
- FO stands for "Fish Only." It refers to a saltwater tank where you only have fish. No live rock and no invertebrates.
- FOWLR stands for "Fish Only WITH Live Rock." The "Fish Only" refers to the part that there won't be any invertebrates in the tank, just fish. The Live Rock refers to bringing in rocks from the ocean that have living micro (and some macro) organisms on them that help with biological filtration.
Reef tanks usually don't have that many fish in them and if they do, the fish will be small or limited in number. Basically, you're growing your reef and you don't want to have fish in there that can damage or eat it.
Most Popular components to a Reef Aquarium
Besides your live rock and some fish for show, most everything you're going to find in a reef aquarium is an invertebrate. Invertebrates are basically animals without backbones. But here are some of the most popular invertebrates you're likely to find in a reef tank:
- soft coral
- hard coral
- sea urchins
- crustaceans (crabs and shrimp)
- tube worms
- mollusks (clams, snails, and octopuses).
Why keep a reef tank? Anybody who's ever stood in front of one will tell you. They are mesmerizing. You can't take your eyes off a reef tank. It's like having a little bit of the ocean, right there in front of you. Pros to keeping reef tanks include:
- Reef tanks provide a welcome challenge
- The beauty and uniqueness found in a reef tank is unparalleled
- Keeping reef tanks helps raise interest in protecting wild coral
Some people just like a challenge. You tell them "it can't be done" or "it's really hard to do," and what do they do? Turn away? No way, they're drawn towards the reef tank and make it their life's dream to successfully keep a reef tank in their home. With a reef tank, you're replicating even more of an ecosystem than a FO or FOWLR tank. You need to account for not just how fish interact with each other, but how fish, corals and invertebrates interact with each other to help support each other in a more sustainable environment. You'll learn more about the biology of organisms and how ecosystems manage themselves than you would with other set-ups.
In terms of the beauty of a reef tank, truly, there is not another experience in the world except for reef snorkeling or scuba diving that will let you appreciate up close what makes a reef tank special. Reef tanks are like none other. The beauty of the corals, anemones, and other invertebrates are unparalleled. There's simply nothing else like it. The relationship between all the different animals in a reef tank just adds to the experience.
Finally, the interest that reef tank owners have in their hobby helps protect the reef environment in the wild. It's hard to appreciate something when you never see it or have no way of understanding what is truly at stake. With reef tank hobbyists, you'll find owners who make it a life style, a life's goal even to protect their "babies" out in the wild, too.
The decision to start a reef tank is not for everybody. Here are some of the main reasons that people find reef tanks too much to take on:
- The challenge above and beyond keeping saltwater tank
- Tank considerations
- Must keep the water circulating
- Costs more
- More filtering required
- Fish selection limited
Keeping invertebrates happy in a tank sounds hard, doesn't it? Corals and anemones are extremely sensitive to their environment. Many people won't even consider just jumping into keeping a reef tank once they learn of all the intricacies. They prefer instead to start with a freshwater tank, then maybe a saltwater tank, and then begin tinkering with keeping a reef tank.
Tank size is another serious consideration. Keeping a reef tank means you can't go small with the aquarium size. The tank shouldn't be too narrow and it needs to be big. Most experts suggest that you should never start with anything smaller than 40 gallons (we're leaving pico and nano tanks out of the picture for the purposes of this article). While the 55 gallon size tank works well for a saltwater tank, you'll want to consider the 70 gallon tank over it for a reef tank since the 70 gallon tank is 18 inches deep whereas the 55 gallon tank is only 13 inches deep (a little shallow from front to back to house a reef). Keep in mind also that with corals, the more brilliant colors comes from strong lighting. The taller your aquarium is, the stronger your lighting will have to be to adequately light the coral.
Let's look at the impact that overcrowding can have on corals. Corals can't be too close to each other or they'll fight for space and food (corals release chemicals and use nematocysts to duke it out with each other). Once corals are stressed out, they'll become susceptible to various diseases. Just like the black plague of the 14th century, disease can wipe out your entire coral population in just days.
One big difference between reef tanks and saltwater tanks without invertebrates is that you must keep the water circulating in an invertebrate tank. Reef tanks require sump pumps to simulate that ocean motion. Otherwise, your corals, anemones and other inverts will all starve to death in a pool of stale water. The water in a reef tank has to be in constant motion to help simulate a real reef out in the wild. While inverts do move, they don't move enough to go out and stalk their prey. Most of them require a lot of help with the currents in the water out in the ocean. You'll need to mimic that action for them at home.
Compare freshwater fish to saltwater fish to keeping a reef tank. Which do you think is the most expensive? By now you've probably guessed it correctly. Keeping a reef tank can be much more expensive. Just about everything costs more. Your tank will cost more, your supplies will cost more (now you've got to worry about salinity plus different foods for your inverts), and you've also got to include your sump equipment. Besides that, corals and other invertebrates are usually more expensive than fish. Even if you can get them at reasonable prices, because they are so much more difficult raising than just freshwater fish or saltwater fish, you'll find that in some cases, until you get your system just right, you'll be keeping a pretty transient population in your reef tank! Some experts estimate that the increase in electrical power requirements can raise your power bill from $10 to $70 more a month!
With reef tanks, you'll find that Protein Skimming needs to be added to your filtering system. Protein skimmers work by collecting organic pollutants before they break down. They catch the organic pollutants by skimming the foam air bubbles that come out of air pumps after they break to the water surface. Protein skimmers usually range between $100 and $500 but really, you'll need to consider how big your tank is before you pick one. The other thing about protein skimmers is that you constantly have to fiddle with their settings to make sure they're working optimally. Another consideration is that you'll need more aeration than you'd find in a freshwater tank. That's because saltwater holds less oxygen than freshwater of the same volume.
Corals and other invertebrates in your tank can limit your selection of fish, as some marine fish will eat or otherwise damage those corals. In general, larger, more aggressive fish (which are often quite pretty) are inappropriate for reef tanks that are more dense with rock and have tasty coral for them to eat. Here is a short list of fish that have been successfully kept in reef tanks (deemed "reef-safe"): Watch out, though, most of these fish are EXTREMELY territorial.
- Damselfish - these will be the last fish you'll want to introduce to your tank or you'll have a very hard time getting other fish into the tank once these guys set up shop.
- Clownfish - keep just a pair per species for the best harmony in your tank.
- Blennies - work well in a reef tank and you don't have to worry about them eating other fish as much as you would with some of the other reef fish
Online Sites related to Reefs
is a great online source for more information on reef tanks
- is a great online forum for those interested in reef aquariums.