Saltwater vs. Freshwater Aquarium | Which Should You Choose?

Thinking of setting up an aquarium in your home or office? Good choice! As mentioned in our post on the benefits of an aquarium, a fish tank makes for a fantastic centerpiece and learning opportunity. It even helps you feel more relaxed! But… between a saltwater vs. freshwater aquarium, which will work better for you?

Let’s have a look at the pros and cons of these two main types of aquariums below. We’ll compare stuff like appearance, cost, maintenance required, and more, so you can decide which direction you want to take your tank in.

Saltwater vs. freshwater aquarium: Pros and cons

Freshwater

Freshwater aquariums are generally considered the more basic option. And that’s pretty accurate; if you want to keep it simple, freshwater is probably the way to go. We tend to recommend it to beginners, as the cost is lower and the livestock isn’t as sensitive.

Here’s what you should know about freshwater aquariums:

Pros

• Livestock: there’s a good variety available, some very colorful. Many species are relatively hardy.
• Plants: you can grow a lush green underwater garden in your tank.
• Cost: starting and maintaining a freshwater tank is something that can be done on a budget. You need less equipment and livestock is cheaper.
• Time: although you still have to perform tests and maintenance, a freshwater tank usually won’t take up too much of your time each week.
• Availability: almost every pet store will carry some freshwater fish and equipment.
• Size: in freshwater, nano means 10 gallons or under. Some folks successfully keep “pico” tanks of 2.5 gallons or less.
• Water: although you do need to use a water conditioner, in many places you’ll be able to fill your tank with tap water.
• Biotope: freshwater habitats (different rivers, streams, lakes, and more) are more varied than saltwater ones (mostly just reef and open water), so you can play around with very specific looks.
• Experience level: in most freshwater tanks, a small mistake won’t usually cause mayhem.

Cons

• Biodiversity: it’s just lower. Freshwater fish and inverts aren’t as extravagant, nor are there as many different species.
• Décor: live plants are nice, but they’re not as colorful and varied as corals, anemones, and seaweeds.
• Complexity: there are less opportunities to observe really unique behaviors and relationships between creatures.

Equipment needed

• Tank (preferably 10+ gallons)
• Filter
• Light
• Heater
• Thermometer
• Simple test kit set
• Water conditioner
• Substrate
• Décor (rocks, driftwood, plants)

The list is longer for planted tanks (trimming equipment, fertilizer, etc.) but still relatively simple.

Price estimate

If you’re good at hunting for bargains on local marketplace websites, you may be able to find a simple, small tank with freshwater equipment for as little as $50-100. Monthly maintenance costs are pretty low, as you generally just need to buy test kit refills and more water conditioner from time to time.

Filling your freshwater aquarium with life usually isn’t too expensive either (although of course, the final cost depends on your preferences). Small fish and simple plants usually cost no more than $5-10 each.

Did you know? If you’re between setting up a freshwater aquarium and a terrarium, you’ll be pleased to know a middle ground exists. It’s called a paludarium. Usually, the bottom layer is water, while the top is reserved for rocks, branches, plants, and moss. You can keep select terrestrial and aquatic creatures, or go for those that like both, such as some types of crabs.

Saltwater

Saltwater aquariums are generally considered more challenging to maintain, but also more versatile in terms of the amount and types of fish and invertebrates you can keep. A lot of people also find the colors in a marine tank more attractive, but of course, that part is pretty subjective!

Here’s what you should keep in mind about saltwater aquariums:

Pros

• Fish: there’s no end to the different types of fish you can potentially keep. Marine fish biodiversity is unmatched. Except maybe by…
• Invertebrates: shrimp, crabs, starfish, molluscs, urchins, and much more! There are some seriously weird invertebrates out there.
• Behavior: you get the opportunity to observe some seriously fascinating symbioses and strange eating habits, among other interesting behaviors.
• Décor: aside from decorative rocks, you can grow a variety of colorful corals, anemones, and even seaweed.
• Equipment: there is a wider range of fancy equipment (and even domotics!) out there for saltwater tanks, which is perfect for tech junkie fishkeepers.
• Challenge: as should be clear by now, saltwater tanks are generally more difficult to maintain. But that also makes it all the more satisfying when things go well!

Cons

• Time: most saltwater tanks require more rigorous maintenance, daily monitoring, and very regular testing to keep things running smoothly.
• Money: everything saltwater is more expensive, and you need more of it. A simple coral cutting or a single fish can cost upwards of $50!
• Experience: a lot of marine livestock is highly sensitive, and the chemical processes involved are sometimes complex.
• Availability: due to the above factors, not all aquarium stores carry marine gear and livestock.
• Size: in saltwater, “nano” refers to pretty much anything below 30 gallons. Small marine tanks are much harder to keep stable than freshwater ones, and therefore not recommended unless you’ve got plenty of experience.
• Water: in most cases, it’s not possible to use tap water in a saltwater tank (not even if you mix it with marine salt).

Equipment needed

To set up a marine aquarium, you need much of the same equipment that you would for a freshwater tank. However, there are a few additional important pieces.

Here’s what you’ll need:

• Tank (preferably 30+ gallons)
• Filter or sump
• Strong light
• Protein skimmer
• Heater
• Thermometer
• Salinity meter
• Full test kit set
• Circulation pumps (often preferable)
• Live rock and sand (often preferable)
• RO/DI water (has to be bought regularly, or you need to install your own unit)
• Special marine salt (unless you buy pre-mixed water)
• Supplements, like calcium and magnesium (often required)

Price estimate

Although buying a used tank and equipment can help keep the cost down, saltwater fishkeeping will never be a great hobby for folks on a budget. Your initial investment is likely to be at least $500 excluding livestock, a number that can skyrocket to $2,000+ if you like something big and fancy.

Once you’ve got the tank, you have to fill it with life, and that’s not cheap either. As mentioned, even small coral pieces and the most basic fish and invertebrates can be seriously pricey.

Maintenance for smaller tanks isn’t too bad in terms of cost, but a saltwater aquarium by no means runs itself for free. Most folks have to buy water for water changes, for example. You may also have to regularly buy special marine salt, supplements, and test kit refills.

Tip: Aquariums come with a “hidden” cost: electricity. This cost will be higher with saltwater tanks, as these contain more equipment that needs to be powered.

Conclusion: Saltwater vs. freshwater aquarium

People sometimes seem to think that any “serious” fishkeepers would go for a saltwater tank, while beginners and “casual” hobbyists stick to freshwater because it’s simpler. Although it’s true that folks often eventually graduate to saltwater, some of the most dedicated aquarists with the most amazing tanks exclusively keep freshwater!

In the end, it all just depends on what suits you and your lifestyle better. We think a saltwater aquarium is right for you if:

• You’re detail-oriented
• You’re willing to dedicate more time
• You’re willing to dedicate more money
• You like bright blues and purples more than soft greens and browns

A freshwater aquarium is right for you if:

• You’re on a budget
• You’re a beginner
• You like more flexibility
• You like the idea of recreating different habitats

PS: Want an aquarium but don’t think you have the time? Or maybe you worry you lack the expertise for something like a nice reef tank? That’s where the FantaSEA Aquariums team comes in!

Just shoot us a message with your ideas and we design, set up, and maintain your dream aquarium for you. All you’ll have to do is enjoy it!