saltwater vs freshwater tank header

The earth is covered in water. In fact, about 75% of the planet is filled with saltwater, brackish, murky, or freshwater in various forms with various levels of salinity.

And all those bodies of water are filled with living creatures – many of which we like to keep at home as pets. Some are warm, tropical bodies of water where gorgeously bright corals and exotic fish live. Some are brackish and murky where beautiful killifish live. Others need cold, freshwater, like goldfish, tetras, and betta – though some say these are brackish water fish.

Some are warm, tropical bodies of water where gorgeously bright corals and exotic fish live. Some are brackish and murky where beautiful killifish live. Others need cold, freshwater, like goldfish, tetras, and betta – though some say these are brackish water fish.

So the big question for new aquarists is this: Which should you keep?

A saltwater vs freshwater tank? What are the saltwater or freshwater aquarium pros and cons? Are saltwater aquariums hard to maintain?

Let’s dive in!

ram cichlid freshwater vs saltwater aquariums

How To Choose Saltwater vs Freshwater Tanks

Ultimately, the answer is going to come down to a few factors based on your preferences and needs. But it can be difficult to decide without further information. So, we’ll dive into the various aspects that will help you decide between a freshwater or marine aquarium.

We’ll look at these things to help you narrow down your options and decide.

  • Beginner friendliness
  • The amount of work required for each
  • Algae growth and cleaning requirements
  • Equipment needs
  • Tank size requirements
  • Cost of purchase
  • Cost of maintenance

Beginner Friendliness of Saltwater VS Freshwater Fish Tanks

A lot of people instantly assume that saltwater aquariums are much too difficult for a newbie to begin with. However, there are challenges to face with both saltwater and freshwater fish tanks and either may prove the right choice for you. It all comes down to a series of choices you make.

Think about the natural freshwater environment compared to the saltwater environment. In the ocean, conditions of the water don’t really change that much. The pH, salinity, chloride levels, etc. remain just about the same from day to day. This means saltwater aquariums need to also remain a consistent, stable environment for those dazzling fish, corals, crustaceans, and other critters.

Freshwater environments, however, experience cyclical changes that happen thanks to things like flooding, drought, et cetera. This means that the chemical composition of the water, temperatures, and other aspects of the environment change inconsistently and dynamically. This ultimately means freshwater fish are more adaptable to changes in their environments.

For anyone not great with details, a freshwater aquarium is going to be easier to maintain as a beginner. Small mistakes will happen with the water chemistry – which can be problematic, even deadly, for saltwater fish that need that consistency.

However, if you’re great with details and willing to take a little risk and do a lot of study beforehand, you may well be able to start with a saltwater aquarium and have your critters thrive. It’s not advised that you start with a nano coral reef tank or other kind of reef aquarium – corals are extremely delicate – or fish only with live rock tank – or FOWLR – as these require significantly more understanding.

But a saltwater fish only tank may well be a great route for you to start with.

All that said – a freshwater tank is easier to start with, but a fish-only saltwater aquarium is absolutely doable for a newbie who’s willing to put in some time for study and experimentation before purchasing the fish and equipment.

Amount of Work Required

Now, let’s take a look at the actual work required for saltwater vs freshwater fish tanks.

There is no actual answer or comparison on the saltwater versus freshwater question. The reason? Every aquarium is different and therefore requires a different level of care.

But, we’ll look at a couple of things that are the components in the way you can compare the two based on your personal desires and preferences.

blue aquarium fish with red strips salt vs freshwater

Types of Fish, Invertebrates, Et Cetera

The types of fish and other critters you stock your aquarium with are going to be a major dictator on the amount of work you put in. If you’re working with a fish only saltwater tank, you should choose low-maintenance fish to decrease the care level. Some of these include:

  • Yellow Tangs
  • Bi-Color Blennies
  • Clownfish
  • Mollies
  • Lawnmower Blennies
  • Watchmen Gobies
  • Royal Gramma Basslets
  • Banggai Cardinalfish
  • Blue Damselfish

You can read up on these and others on a variety of sites.

If you choose to go freshwater, there are even more options of easy-care freshwater fish that add as much color and intrigue as the saltwater species. Some of those include:

There are many others, as well, that you can study up on and examine photos to see which would be suitable for your intentions.

And whichever type of tank you keep, the invertebrates you choose can also impact the care level needed.

Freshwater snails, for example, can help diminish your cleaning time.

Scavengers like shrimp can help reduce your maintenance time in saltwater aquariums. If possible, choosing some of these critters are definitely a benefit for the aquarium and yourself.

Choosing to maintain a tank of a single species, however, can also reduce the care level. The reason? A beginning aquarist can learn and study a single species heavily and become very knowledgeable on that one species. This means less balancing of the environment for multiple critters as well.

Whatever route you go with these creatures, always make sure you choose ones that are compatible with the same environmental conditions. Otherwise, you’ll find the care level has skyrocketed and your ability to keep your vivid pets alive crashes.

The Equipment You Choose to Invest In

The second aspect that determines the maintenance and care level of an aquarium is the type of devices you choose to invest in.

Some are absolutely required for all tanks – filters, for example, that keep water pure and clean for your fish that must live chemical free – while others are nice to have for maintenance’s sake but are not mandatory for the health of your fish.

We’ll talk more about the equipment requirements in greater detail below.

The Size of the Aquarium

The final thing I’d like to note that has a huge impact on your aquarium care level is the actual size of the aquarium and how many creatures you have living inside it.

Many hobbyists think that smaller aquariums will equivocate a smaller amount of care. This is actually the opposite of true.


The smaller the environment, the more precise the care must be.

Many folks also tend to think that smaller aquariums are suited to specific common pet fish – think goldfish and bettas in their tiny, decorative fishbowls – but this is also not true. For example, according to Tropical Fish Care Guides, goldfish can grow up to 16 inches and live up to 25 years in a large enough tank or pond!

Before you purchase your fish tank, be sure to study up on the care and needs for the fish you’d like to have. You could be surprised at the tank size requirements and may well choose a different species of fish or a different aquarium based on these needs.

red and white fish swimming in aquarium

Algae Growth and Cleaning Requirements

There are several factors that are involved in the cleaning and algae growth aspects of your aquarium. The first and foremost is the plants and animals that are kept inside the aquarium. Second is the equipment you use. Third is your personal time investment into the maintenance.

The Plants and Animals

Freshwater aquariums are often something called a planted tank – meaning there is an abundance of aquatic plants inside the water.

These plants not only provide those little freshwater fish with places to hide and food to eat, but they also consume the nutrients that algae would need to grow. This heavily restricts the growth of said algae, which benefits the aquarium and the aquarium keeper.

Plants for saltwater tanks are a bit harder to come by. Which means those nutrients are ripe for algae to eat and grow with. This means you need more heavily involved equipment for cleaning – items such as protein skimmers, for example, are used to remove waste and compounds that algae thrive on.

The Lighting

The amount of lighting in your aquarium also affects the algae growth levels. Low and mid-light tanks have lighter algae growth. High-light tanks tend to constantly battle against the algae problem.

Your Participation

For saltwater aquarium keepers, you’ll need to be diligent with your maintenance to keep the algae growth down. Even with those bright lights and that lack of plants, you can absolutely control algae through regular water changes – study this closely, though, as too often can harm your aquarium – vacuuming your gravel and using that protein skimmer as directed.

It’s also important for all aquariums to consistently clean up any excess food immediately after feeding, check the pH and balances in the aquarium – ammonia and nitrates not only grow algae but they also kill fish! – and check and maintain the water temperatures.

Equipment Needs

There are certain things that all aquariums require – filters, fish nets, food, gravel vacuums, et cetera – but there are some specific equipment needs that vary between saltwater vs freshwater fish tanks.

Saltwater Aquarium Checklist

Freshwater Aquarium Checklist

  • Aquarium/fish tank
  • Water filter and filter media
  • Substrate
  • Food
  • Live plants
  • Lighting
  • Testing kits
  • Fish net
  • Thermometer and heater
  • Air stones and air pumps
  • Water pump or powerhead

As you can see, many of the items are the same on both lists. The saltwater system does have a few extra requirements for optimum health, though, which does result in a heftier setup price tag and maintenance costs over time (especially for paludariums).

Tank Size Requirements

Generally speaking, yes, saltwater fish tend to be larger and have a need for larger aquarium sizes. But many of the freshwater fish that people assume do well in tiny tanks actually require much larger aquariums.

Don’t base your decision on a saltwater vs freshwater fish tank simply on the idea that one requires a larger tank than the other.

The species of fish and the types of other critters, plants, et cetera, are actually what determine your aquarium’s size requirements. Be sure to study your stocking choices instead.

Here are a few examples of fish tank size requirements based on species, which may give you some ideas of what you may be considering here. All the minimum sizes listed are based on a single fish of the species. These sizes expand based on pairings and schooling.

Betta fish5 gallons
Cichlids20 gallons
Goldfish20 gallons
Angelfish10 gallons
Guppies5 gallons
Blue Damselfish30 gallons
Yellow Tangs55 gallons
Coral Beauty Angelfish70 gallons
Clownfish20 gallons
Kleins Butterflyfish120 gallons

As you can see, the minimum tank size varies greatly and really is based upon species, not natural environment – saltwater vs freshwater tank. As you look at the list, you will see typically it is the saltwater fish that require larger tanks, but some freshwater fish require larger tanks as well.

Cost of Purchase

There are several factors involved in the initial setup costs for your aquarium. The heftiest costs, of course, are the equipment items listed above. The types of fish you stock, the live plants, the specific brands of substrates and devices also all effect the cost of your aquarium.

So, we’re asking:

How much is a saltwater tank? And how much is a freshwater tank?

The base cost of aquarium, fish net, water pump, air pump and air stones, et cetera that both types of tanks require will vary widely based on the brands you choose to purchase.

However, the average cost of these items will come out to between $75 and $200 in most cases for a basic kit setup. Once you tack on specifics of a particular brand, the types of fish and plants you stock, the foods you choose, et cetera, that price goes up.

If you’re starting with low-end to mid-level equipment, you can probably set your budget at about $200 to $300 – including inexpensive fish and plants – to start. If you prefer to dive right into the higher-end equipment, you’re looking at $350 plus for your aquarium setup.

saltwater reef aquarium

Cost of Maintenance

After your initial setup cost, you will sometimes have to replace equipment, fish, aquatic plants, et cetera, of course. But you’ll also have those regular costs of food, testing kit refills, et cetera. These prices, again, vary greatly on the brands you choose to use.

The average cost of maintaining a small to mid-sized aquarium, however, is probably going to range between $150 to $200 per year for the food and other regular maintenance items.

This doesn’t really vary greatly between freshwater and saltwater aquariums, however, except that with marine tanks, you also need to add in the cost of marine salt.

You Should Keep a Saltwater Tank If…

There are a few key components to who should and should not keep a saltwater aquarium.

The first and foremost important factor in keeping a saltwater aquarium for the first time – especially if you have never kept a freshwater tank – is the willingness and time to research your saltwater aquarium’s needs.

Here are just a few of the things you’ll need to research and understand before purchasing anything:

  • What kinds of saltwater fish do you want to keep?
  • What size tank do those fish require? How many gallons per fish?
  • How many of those fish can be kept together? Is the fish species a community fish or a loner? Do they do well as mated pairs or must they be kept separate except during breeding?
  • What type of food do the fishes need?
  • What types of aquarium décor items does the fish do best with?
  • What kind of substrate should your aquarium have? Should it be gravel, sand, or a combination thereof? Or would crushed coral be best?
  • At what temperature must you maintain the water?
  • What pH range is required for the fish?
  • How much lighting do the fish need?
  • Will you need a wave maker?
  • Should you keep the fish with invertebrates?

As you can tell, there’s a lot to consider.

If you’ve got the time and interest to learn all these things – and a few others – you are well-suited to working with a saltwater tank as a beginner.

If you’re not able to do all this, you should start out with a freshwater tank instead.

You Should Keep a Freshwater Tank If…

All the above being said, you’re probably more suited to freshwater fish keeping if you’re short on time and low on the interest in researching.

You’ll still need to do some for each species of fish or plant you want to stock, but otherwise, freshwater fish keeping is a fairly low maintenance hobby, if you choose your stock properly.

Aim for easy-care and beginner-friendly fish for best freshwater aquarium results.

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