Saltwater vs Freshwater Aquariums: 21 Pros and Cons

If you are a complete beginner as an aquarium enthusiast, you might be unsure which tank to start with. There are quite a few differences between a community of fish in saltwater or one in freshwater, including equipment, cost, time, and of course, the specific fish themselves.

Saltwater versus Freshwater Tanks: Everything You Need to Know

If you are a complete beginner as an aquarium enthusiast, you might be unsure which tank to start with. There are quite a few differences between a community of fish in saltwater or one in freshwater, including equipment, cost, time, and of course, the specific fish themselves.

In this article, we will break down the differences between the two types of fishkeeping, including the cost and considerations of each, and who they might be best suited to.

Both kinds of aquariums have their own advantages and disadvantages, and you will likely find that one style of fishkeeping is perfect for you.

Saltwater Tanks and Saltwater Fish

While the aquariums are incredibly beautiful, many fish enthusiasts might be swayed from starting with a saltwater system from fear of cost or difficulty. Let’s have a look at the nitty gritty of saltwater aquariums and work out if you should get into this kind of fishkeeping.

What Equipment do you need for a Saltwater Tank?

You will need a big enough tank for the size of fish you would like to keep, remembering that some can grow quite big, and many of them like a lot of space to move around or hide. Some of them also prefer to be quite solitary and prefer to keep to themselves.

Saltwater holds less oxygen than freshwater, so you need a bigger tank than you would with freshwater fish, basically so your little guys can breathe. In fact, research tell us that saltwater only contains around 80% of the oxygen that freshwater holds.

You will need a strong enough stand for the tank and all of the water – it is best to buy both together or discuss with your supplier which stand would be best for your tank.

You will need:

  • Aquarium
  • Stand
  • Gravel for the base
  • Saltwater mix (you can’t just add table salt to water)
  • Live rock
  • Water filter
  • Powerhead
  • Lighting
  • Protein skimmer
  • Water testing kit
  • Ammonia and other chemicals to maintain the balance of the water

If you are going to keep more than one fish in your aquarium, you will also need a smaller tank which is your hospital/quarantine tank. Newly acquired fish need to go into this for a little while before introducing them to the rest of the community.

You will also need a supply of cleaning products for your tank which are specialised, and can’t be swapped for general household ones.

On top of this you will need fish, and to supply the right food for them.

How much does a Saltwater Tank system cost?

A saltwater tank system, as well as the fish you will buy to populate it, are both more expensive than freshwater systems.

Saltwater systems need to be properly monitored to make sure that the balance of salt and other chemicals in the water are fine for your fish, as well as maintaining the warm temperature that tropical fish will thrive in.

Cost will also depend on how big your tank is. With saltwater fish, depending on the breed, they can be temperamental and will need the right amount of personal space to be happy. You don’t want to overcrowd a tank or buy a tank that is small if you like to own some larger breeds of fish.

The rarer your saltwater fish breeds, the more expensive they will be to source, as well as to feed. Plus, if you choose rare and expensive fish then you probably want to invest in a good-quality tank, heater and filtration system.

In terms of cost, you can set up a perfectly good saltwater system relatively cheaply, but it will be smaller and hold less fish, and only suitable for the hardier breeds.

Generally, you would pay at least $500 for all of the equipment you need for a saltwater system, then fish and food would be additional.

You will also need to pay for salt as well as water testing items regularly. Size matters and unlike freshwater aquariums smaller size tanks are much harder to keep. Nano aquariums are well known for being beautiful but also very hard to keep and maintain perfect water conditions.

We would never recommend setting up a saltwater aquarium less than 75 Gallons.

How much Time and Effort is needed to look after a Saltwater System?

You need to allow at least a month when you first set up your saltwater tank before you add any fish. This allows the rock and plants to get established and the water levels to adjust to a healthy level for your fish.

A saltwater tank must be monitored daily to make sure that the salt levels of the water are balanced. Because, in the wild, their environment is fairly stable in terms of temperature, pH level, salinity, etc., these kinds of fish are used to constant conditions.

Saltwater tanks grow algae quite quickly, because they have less living plants in them than freshwater tanks (living plants help to slow down the algae build-up). You will need to clean a saltwater tank more often to keep on top of the algae and keep your fish happy and healthy.

Many saltwater fish are picky eaters or have small stomachs, and need to be fed several small meals a day rather than one big one. You generally can’t go away and leave your tank for days for a short break – they will need regular looking after. You can, however, use an automatic fish food feeder to keep them correctly feed at the right times whilst your away.

What Fish Breeds are Saltwater Fish?

The fish that flourish in saltwater are generally the most beautiful ones on earth, and you will be greatly rewarded for all the cost and effort in your daily rainbow ballet from your stunning little friends.

Saltwater fish are rarer than freshwater ones, and often more temperamental, but also can have more personality and characteristics than their freshwater counterparts.

do fish in captivity live longer?

The number of breeds you can have in your aquarium is literally limitless, but some of the most popular breeds include:

  • Clownfish
  • Tangs
  • Hawkfish
  • Basslets
  • Gobies
  • Dartfish
  • Butterfly fish
  • Seahorses

The clownfish is one of the most popular saltwater fish thanks to the amazing relationship they have with anemones. An, of course, the Disney film Neno which made them famous the world over.

Are there any Special Considerations in owning Saltwater Tanks?

A saltwater system is a more complex system to set up, and harder to move once you’ve put it in place – so, make sure that you get the location in your home right the first time.

Your tank should be away from direct sunlight as this will speed up algae growth, and you also don’t want the temperature of the tank fluctuating too much on its own. You need a space that is well-ventilated.

Many people start with a smaller tank thinking that they will effectively wade into saltwater fishkeeping, but there can be drawbacks to this.

Saltwater tanks can take a while to establish, and for the fish to acclimatise and living rock to flourish. None of the inhabitants transfer easily to a new tank, so it may be better to start with the bigger system you would like to end up with from the beginning.

It is recommended that even if you are a beginner to saltwater fish keeping, it would be better to start with the bigger tank. Any mistakes you make are likely easier to correct with a bigger tank, and your fish are more likely to be healthy and thrive with less need for troubleshooting. Read all about the 30 fishkeeping Common mistakes made by most beginners.

Who is a Saltwater Tank best for?

A saltwater aquarium may not be best for people who don’t have time to keep the system constant. If you are unsure if you are going to love fishkeeping, then don’t start with saltwater.

Also, if you don’t have the space for a bigger tank, you may consider freshwater fish instead.

However, if you are passionate about these gorgeous and exciting fish, then don’t be swayed from getting into saltwater fishkeeping just because you are a beginner – this is more about love and commitment than experience.

Nano reef tank
Nano Reef Tanks are not for beginners Photo Credits @nano-reef & Podrod

You can get a basic, fish only saltwater aquarium set-up which is less expensive than a full reef community. But with the beauty and variety of fish available, most saltwater enthusiasts wouldn’t bother with basic.

Consider owning a saltwater aquarium as you would getting a dog – these are pets who need care and attention, and if you aren’t willing to commit to that on an ongoing basis then they may not be right for you.

Freshwater Tanks and Freshwater Fish

Far more than just a goldfish in a bowl, a freshwater aquarium can contain a number of stunning fish, and be a gorgeous and interesting addition to your home. Especially when you consider the breeds of tropical freshwater fish available to own, your tank community will certainly be colourful and filled with personality.

Even if we go back to the popular little goldfish, there are actually many more exciting varieties that you are probably not familiar with. Most children love to give their fish names, it’s part of the fun of keeping fish.

What Equipment do you need for a Freshwater Tank?

At its very basic, you can technically own a freshwater tank with just a bowl and some water. While this is possible, it’s not recommended, as your freshwater fish do need a little more than that to be happy and healthy.

But you can start with a fairly small set-up if you only want one fish for example, and your initial outlay needn’t be much.

Because freshwater fish can be happy in small tanks, you don’t need to buy a specialised stand unless you are buying a bigger tank. A smaller one will sit fine on a table or desk.

You will need:

  • Aquarium
  • Gravel for the base
  • Filter
  • Lighting
  • Plants, decorations and places for fish to hide
  • Water testing kit

If you are considering keeping a larger freshwater community you should again have a smaller quarantine tank for sick fish or when bringing in newcomers.

Some freshwater fish are happy in cold or room temperature water, while others, such as tropical freshwater fish, will need a heater.


How much does a Freshwater Tank system cost?

Cost will depend on a few factors including the size of the aquarium and the community of fish, as well as if you wanted to keep tropical freshwater varieties or just your hardy little friend, Goldy.

You can generally start up a freshwater system for between $100-$300. Fish and food will be extra, but these cost far less than saltwater, and the ongoing costs are also much less.

How much Time and Effort is needed to look after a Freshwater System?

Freshwater fish, in the wild, are used to rough terrain and changing conditions. They go through periods of drought and flood, and are a bit more used to the conditions and chemical make-up of their environment changing.

Hence, they are more adaptable to fluctuations in the water, and you don’t need to be quite as vigilant or constant about the water condition as you do when caring for saltwater fish.

How to do a water change

The living plants in your aquarium will help to slow down the algae growth so if you invest in a few good plants you won’t need to clean your tank or change the water as often.

You should still clean your tank regularly and test and change a portion of the water weekly.

Your fish should be fed daily, but many of the hardier ones can go a day in between feeds if you want to head away for the weekend for example.

What Fish Breeds are Freshwater Fish?

There are fewer options in freshwater fresh, and the ones readily available aren’t as beautiful as their saltwater cousins. Some of the benefits of freshwater fish include that there are more schooling varieties, and you can fit more fish in your tank because of the oxygen in the water.

You can source lots of interesting and colourful freshwater fish and fill your tank with them, watching them dance and interact.

Popular freshwater breeds include:

Are there any Special Considerations in owning Freshwater Tanks?

There are fewer worries and considerations when looking after a freshwater tank, because the fish by nature are hardier and more adaptable to fluctuations in their environment.

You will still need to change around 10-15% of the water weekly to look after your fish, and clean the tank regularly. Take care with the breeds you buy and make sure that each one has what they need in terms of space, food and décor. Don’t put breeds in together that are aggressive or predatory – you will still need to your homework if you are setting up a freshwater community

fish tank water changes

Who is a Freshwater Tank best for?

A freshwater tank is better for people who aren’t sure about the level of care and commitment they will be able to devote to looking after fish, as well as those who don’t have the space in their home for a larger tank.

Set-up and ongoing costs for freshwater tanks are less than for saltwater, so if you have less to spend, or are getting a system for a child for example then freshwater could be the way to go.

Conclusion: Saltwater versus Freshwater: Which one is better?

Well, that is the biggest question.

Neither is better in my opinion, both can be wonderful. Both can be beautiful, filled with interesting fish with colourful personalities, and both are wonderfully soothing to watch.

Owning a fishtank has lovely calming powers and brings with it the stress reduction of owning any pet.

While saltwater tanks cost more and generally take up more space, the biggest difference between the two is the level of commitment and care you have to devote. Don’t be swayed from owning a saltwater tank just because you are a beginner, but if you are uncertain if fishkeeping is for you, freshwater systems may be a better place to start.

If this article has tipped you in favor of Tropical Fish then you may be wise to read our complete guide to starting a fish tank. It has all the information you’ll need to set up your fish tank without making any mistakes.

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