Before we talk about size; before we talk about setup; before we talk about care and feeding; before, in fact, we go any further down the planning path of an aquarium, we need to figure out what we like and  what we want to do with our aquarium lives, so to speak.  This is where we make the decision of what our first tank is going to be.  To do that, we have to introduce the types of aquarium setups that exist, and the list is pretty short: 

• Freshwater Aquariums

• Saltwater Fish Only With Live Rock (FOWLR) Aquariums

• Saltwater Reef Aquariums

• Specialty Aquariums

Let's look at the considerations and complexities associated with each of these types of aquariums:

Freshwater Aquariums 

Freshwater aquariums are EXTREMELY popular in the United States and around the world.  According to the American Pet Products Association, there were an estimated 153.3 million pet fish in U.S. households in 2020. Of these, 141.4 million were freshwater fish and 11.9 million were saltwater fish. This means that freshwater fish make up about 92% of all pet fish in U.S. households.  If you've decided to start with a freshwater tank, you're in good company!

Are you surprised by this statement?  It turns out there are a few reasons why freshwater aquariums are more popular than saltwater aquariums. 

• • • First, freshwater fish are generally easier to care for than saltwater fish. They require less specialized equipment and can tolerate a wider range of water conditions, which is much more forgiving on the hobbyist.   Freshwater aquariums also allow the hobbyists to integrate plant life into their tank for a truly amazing ecosystem to care for and enjoy.

    • Second, freshwater fish are more affordable than saltwater fish. They are often less expensive to purchase and to feed as well.   Lifespans of freshwater fish trend in two clusters: 1 - 5 year lifespans for fish such as Guppies, Mollies, and Betta fish; and 10 - 20 year lifespans for fish such as Goldfish, Oscars, and Discus.

    • Third, there is a wider variety of freshwater fish to choose from than saltwater fish. This makes it easier to find fish that are compatible with each other and that will thrive in the conditions of your aquarium.   It is important to only keep like tempered fish together in a tank and the new hobbyists will find that many fish stores separate their fish stock into groups: passive, semi-aggressive, and aggressive.  Keeping fish from each of these groups in a single tank will become problematic for the hobbyists.

  There are some complexities that the new hobbyist should be aware of if this the style of tank they have chosen:

• Water quality problems: One of the most common problems new hobbyists run into is poor water quality. This can be caused by a number of factors, such as stocking the tank too quickly, overstocking the tank, overfeeding the tank, not cleaning the tank regularly, or using untreated/undertreated tap water.  
  Poor water quality can lead to health problems for fish, such as fin rot, ammonia poisoning, and nitrite poisoning.  Water quality is best managed weekly and is most easily regulated via water changes, tank and substrate cleaning, and good filtration.  The hobbyist can expect to spend between 1-2 hours per week in maintenance tasks on a freshwater tank (more with larger tanks.)

• Fish compatibility problems: As mentioned above, another common problem is fish compatibility. Not all fish can live together peacefully and it is very important to do your research before adding fish to your tank to make sure that they are compatible with each other.  Incompatibility can lead to fish stress, physical damage to the fish such as fin nip or ulcers, and ultimately fish death.  

• Plant problems: Plants can also be a problem for new hobbyists. Some plants are difficult to care for and can die quickly; some cannot be hosted without highly specialized equipment, chemical additives, and enhanced lighting. It is important to choose plants that are easy to care for and that will thrive in the conditions of your aquarium as a new hobbyist because plants that are struggling can cause additional issues with water quality that can harm your fish.

• Algae problems: Algae is the most common problem in freshwater aquariums. Algae can grow quickly and can make your tank look unsightly, in addition to depleting the oxygen and nutrient levels in the tank.  Thankfully, there are a number of ways to control algae, from natural predators who eat algae (Black Mollies are my personal heroes in this department): simple (and surprisingly affordable) equipment solutions including using a good quality filter; reducing the amount of light in your tank as well as the duration of the lighting schedule; and good tank husbandry such as removing any dead or dying plant materials.

• Fish diseases: Fish can get sick, just like any other animal. It is important to be aware of the signs of fish disease so that you can treat it promptly. If you see any signs of illness in your fish, such as lethargy, loss of appetite, or changes in color, it is important to isolate the fish in a quarantine tank for treatment.  Keeping your fish fed with high quality foods, keeping their environment peaceful and stress free, and keeping your water quality high are easy ways to reduce the amount of disease your fish will encounter.

  Saltwater Aquariums

Saltwater Aquariums are the supercars of the Aquarium Industry: more expensive, typically larger in scale and complexity, frequently coupled with surprisingly complex technologies, and hosting the biggest, brightest, and most dramatic livestock the industry has to offer.  These tanks are highly sought after showpieces comparable in beauty and price to art, and can be the most rewarding experience a hobbyist will have as the tank grows and matures with time.  Yet, just like supercars, when things go wrong the results can be disastrous.  Let's take a look at the two branches most common in the saltwater side of the hobby:

Fish Only With Live Rock (FOWLR) Aquariums:

Let's start with the answer to the obvious question: What is Live Rock and why do I need it?  It's a great question because it applies to ALL saltwater aquariums (well, maybe not to an empty one) and your tank won't survive without it.  "Live rock" is rock that is home to a variety of beneficial bacteria that help to convert ammonia (what fish breathe out into the water) and nitrites (fish excrement, decaying food) into less harmful nitrates (the last stage of the Nitrogen cycle). This is essential for maintaining a healthy aquarium because without these bacteria, there is nothing to drive the engine that keeps your ecosystem alive.  We'll go into deeper discussions of live rock in a future post.  

So, why do people choose FOWLR tanks over Reef tanks?  

• • •  Each layer of complexity in this hobby adds additional costs to the hobbyist in order to maintain and manage said complexities.  Thus, while more expensive than freshwater, FOWLR aquariums are less expensive than reef aquariums.  

    • Beyond cost considerations, FOWLR tanks offer the hobbyist an opportunity to keep fish that are not compatible with corals.  As we'll see in the next section, corals are one of the major financial investments in the hobby.  But the ocean's inhabitants don't care, and what you call an investment will often be considered a lunch to a large variety of saltwater fish.  To prevent your prized polyps from becoming fish food, many hobbyists will set up a "predator tank" or FOWLR tank to host fish including Corallivores and Dentivores (fish that eat or damage corals) as well as Oviparous and Aggressive fish.  

    • FOWLR tanks are also a great start for the hobbyists who eventually want to introduce corals, but but who want to start with a less daunting challenge on day one.

  The hobbyist starting a new FOWLR tank will still need to plan for the complexities most common in the hobby:

• Water quality: Saltwater aquariums require very specific water conditions in order to be healthy. The pH, salinity, and temperature of the water must be carefully monitored and maintained within a narrow range of tolerances.  

• Live rock: As mentioned above, live rock provides a home for beneficial bacteria that help to keep the water clean and healthy. However, live rock can be expensive for fully-biomed rock - rock that has an established, self-perpetuating bacterial colony.  Also frustrating is that even though our tanks can't survive without live rock, it is notorious for introducing unwanted pests and diseases into the aquarium. 

• "Dry" live rock is cheaper than Live Rock because it's easier to create, store/maintain, and ship; essentially, Dry Rock is rock that is ideal to host bacteria, but isn't yet populated with bacteria.  This is rock you bake in your aquarium just like you bake a cake; however, it can take a long time to populate dry rock into live rock, i.e. rock with the levels of bacteria necessary to support the needs of the living inhabitants in your tank.  As an analogy, think of a home in Arizona in the summer: one fan is potentially enough for one person to survive the heat, but not enough to meet the cooling needs of the entire household - so until enough fans (bacteria) are present in said home, we can't have any more guests over (add more fish to our tank.)  

• Maintenance: FOWLR tanks require regular maintenance including water changes, filtration and equipment cleaning, and display tank inspections for signs of algae or pests.  The hobbyist should budget 2 to 4 hours per week in maintenance tasks to keep the tank healthy.

Saltwater Reef Aquariums:  

There are a variety of configurations that the new hobbyists might run into when learning about reef tanks including (in order of difficulty to maintain):

• Soft coral tanks: Soft corals are a type of coral that does not have a hard skeleton. They are easier to care for than hard corals, making them a good option for beginners.

• LPS coral tanks: LPS stands for "large polyp stony." LPS corals are a type of hard coral that has large polyps. They are a popular choice for reef tanks because they are relatively easy to care for and come in a variety of colors and shapes.

• SPS coral tanks: SPS stands for "small polyp stony." SPS corals are a type of hard coral that has small polyps. They are more demanding to care for than LPS corals, but they can be very beautiful.

• Mixed reef tanks: Mixed reef tanks contain a variety of corals, including soft corals, LPS corals, and SPS corals. Mixed reef tanks are considered the most demanding to care for because of the need to balance the specific care requirements for each type of coral, plus fish, all within a single tank.  If a FOWLR tank is the mid-engine Corvette of the aquarium world, then mixed reef tank is the Bugatti - the most beautiful, most dramatic, and most expensive variety to own.

 Reef Tanks, despite - or maybe because of- their complexity are rewarding for a variety of reasons, including (but not limited to:

• Risk Vs. Reward: Some people enjoy the challenge of keeping a delicate ecosystem alive and enjoy the sense of accomplishment that comes from creating a thriving reef tank that they've grown from nothing into a showroom quality ecosystem. 

• Living Art: There are few places outside of remote ocean destinations where people can enjoy the beauty and brilliance of living corals that react to food, fish, light, and even provide unique experiences at night.  Combining that with the beauty of saltwater fish and the hobbyist has a masterpiece worthy of The Louvre Museum or the Metropolitan Art Museum.   

• Community and camaraderie: although true for any type of tank, my experience has shown me that the community of hobbyists in the reefing community are some of the most communal with others; this isn't necessarily because these are more sociable people, but rather because the complexity experienced in this sector of the hobby necessitates the exchange of information with others who are also in the hobby.  By way of analogy, there are many different types of dog owners, from those who have dogs as utilitarian helpers to those who breed and show their four-legged friends; the latter is more likely to know others in the community of dog owners and to know more about the specific aspects of the dog breeds.  The same holds true for aquarium owners, and reefing tank owners are on the communal end of that spectrum.

• Bragging rights: some people collect cars; some people covet the exclusivity of premier golf resorts; some people have passports full of entry stamps from around the world.  Some people in the reefing community collect exclusive / rare corals that are so coveted that they can (and do) sell for hundreds, thousands, and even tens of thousands of dollars (this last being a very rarified club.)  Not long ago we saw certain exclusive Torches going into the four digit dollar sign range; more recently we've seen Bounce Mushrooms hitting even higher numbers.  Owning one of these is the goal of many in the hobby. 

  So, what should the hobbyist expect in terms of complexities in reefing?  Here are some of the most common failure vectors of a reef tank:

• Water quality problems: Reef tanks require very specific water conditions that must be managed in a very tight tolerance.  Small variances in alkalinity, PH, temperature, oxygenation, and water movement can lead to a catastrophic failures that will only be discovered once it starts killing corals and fish.

• Algae blooms: Algae is the number one struggle that the new hobbyist (and experienced as well!) will encounter.  It can quickly take over a reef tank if it is not properly managed, starving out your corals, competing for resources, and disrupting the balance of your water chemistry.  There is a saying in the reefing hobby that "Nothing Good Happens Quickly;" it is also true that in most cases "Nothing Bad Happens Quickly" either - but algae is one of those situations that bucks the trend.  An aggressive algae bloom won't happen on it's own overnight; but once the conditions that support an algae bloom get to the tipping point in your tank, the appearance of the algae itself will go from little/none to full blow garden within what seems like hours.

• Corals getting sick: Corals can get sick for a variety of reasons, but primarily due to two culprits: water conditions and pests. It is important to be able to identify and treat coral diseases as soon as they start, and inexperience is a deterrent to the new hobbyist in winning this battle.  I don't know of anyone in this hobby who hasn't lost corals; it's a painful part of the hobby because even modest corals are expensive to buy and maintain.

• Fish getting sick: Reef tanks require fish to provide the nutrients needed to grow (uneaten food and fish excrement end up as coral food.)  But, fish can, and do, get sick for a variety of reasons. It is ju8st as important to be able to identify and treat fish diseases as it is to detect and identify coral diseases.  

• Mechanical failures: Reef tanks require a lot of specialized equipment to keep the narrow tolerances necessary to keep corals healthy. If any of this equipment fails, it can have a devastating impact on the tank.  The NUMBER ONE mechanical failure in any tank is a heater failure.  A heater that fails off is far, far better than a heater that fails on; but unless you have the proper alarms to identify that the heater has failed, you likely won't notice the mechanical failure until you see the impacts on your tank inhabitants.  For this reason I (and many others) recommend fail-over backup equipment combined with system monitoring to keep you aware of what is going on at all times, and a backup to keep the tank healthy until you can resolve the identified issue.  And even though this is simple logic, these back up systems are extra cost added to a system that is already at the far end of the expense spectrum.    

• Maintenance: depending on any number of factors from size of the tank to the species maintained within it, the hobbyist should expect to spend time EVERY DAY in maintaining their reef tank.  For example, salinity in the tank should be as close to 1.025 specific gravity (or 35 parts salt per thousand parts water - i.e. 35 ppt;)  however, salt does not evaporate, only the water in which it was mixed.  Therefore,  a saltwater tank will experience evaporation of 1 to 2% of its water every day.  If the hobbyist neglects to add water (RO/DI water) back to the system to make up for the water lost to evaporation, the salinity in the tank will increase.   Consider a 100 gallon tank with a specific gravity of 1.025.  After one day, that tank now holds 98 gallons of water, resulting in a specific gravity of 1.0275; after three days the specific gravity will be 1.0306 (these are estimates).  Corals can tolerate short, infrequent exposure to higher salinity, but they start to show signs of stress when the specific gravity of the water is outside of the range of 1.020 to 1.025.  Stability in salinity is the key, and that means the hobbyist must know what conditions have changed at any time, and what must be done to resolve the issue. 

Specialty Aquariums (jellyfish, mangrove aquariums, etc.):

Specialty aquariums range from very easy to very specialized and are typically not something I recommend to those new in the hobby.  That said, some specialty aquariums are very rewarding and some are even beneficial in combination with saltwater tanks.  Some of the most common speciality tanks are:

• • • Low flow tanks for unique fish such as Anemones or Pipefish.

    • Mangrove Tanks, which are prized for their ability to moderate nitrates

    • Species-specific tanks, such as Jellyfish, Shark, and Octopus tanks (to name just a few of the more popular).  

As these tanks are typically outside of the consideration for most beginners, I will not dive deep into this subject at this time.  

I hope this helps you decide which type of aquarium you would want to start with. Let me know if you have any other questions by joining our VTC Facebook page!

(1) Tips for Setting Up A Fish-Only-With-Live-Rock (FOWLR) Aquarium. https://www.petcoach.co/article/tips-for-setting-up-a-fish-only-with-live-rock-fowlr-aquari.

(2) Fish-Only, FOWLR, or Reef: Which Aquarium Setup is Right For You?. https://www.liveaquaria.com/article/223/?aid=223.

(3) What Is a Fish-Only Saltwater System? - The Spruce Pets. https://www.thesprucepets.com/what-is-fish-only-saltwater-system-2925655.