Saltwater vs Freshwater Aquarium – Everything You Need to Know to Make a Choice

If you are looking to have your very own at-home aquarium, the very first decision you should make is if you want a saltwater or freshwater tank. There are pros and cons to each, and neither option is better than the other. It all depends on what you want from your tank as a fish owner.

Before we begin, something to note is that saltwater is found in the oceans around the world, while freshwater is usually found in rivers and lakes. This impacts how the water differentiates and how the maintenance is different between the two.

So, let’s dive into all the factors that you should consider when choosing between a freshwater or saltwater aquarium.


Saltwater vs Freshwater Aquarium: The Main Difference

There are tons of small differences that make saltwater and freshwater tanks different from one another: plants.

In a freshwater aquarium, plants are a lot more utilized for both decoration and functionality purposes. Plants are beneficial to freshwater aquariums because they are able to absorb the nutrients that algae would usually absorb. Therefore, algae growth is less common in these tanks.

In a saltwater aquarium, plants are more scarce. This means that algae growth is more common in saltwater tanks. But, this can be avoided with frequent cleaning of the tank and monitoring the tank’s water. Another method you can use to avoid algae growth in saltwater tanks is to use dimmer lighting. Brighter lighting tends to stimulate the growth of algae.


Water changes – As far as water maintenance goes, saltwater tanks do require a bit more maintenance. This is because of how time-consuming it is to mix the salt into the saltwater. Depending on what salt you have, it will dissolve at different speeds. However, with different methods, you can easily make this process go by faster and smoother. With freshwater aquariums, you must treat the tap water in order to neutralize any harmful chemicals that may infect your tank.

Salinity – Salinity is one of the main things to keep an eye out for when you have a saltwater tank because it can make or break the health of the tank. Saltwater contains a high enough salinity level like the salinity level in the ocean. Freshwater has small amounts of salt but not enough to call it saltwater.

Color – Saltwater tanks definitely win when it comes to color. You can’t get much better than a saltwater reef tank. The bright corals and vibrant fish that are specific to saltwater tanks are astonishing to look at it. Of course, there are still brightly colored freshwater fish, but you can’t get much brighter than saltwater fish.

Plants – As I mentioned before, the main difference between freshwater and saltwater tanks is the plants. Freshwater tanks are much more likely to be seen with plants in them. However, saltwater tanks are able to have corals which freshwater tanks cannot hold. Corals make a great addition to your tank both functionally and aesthetically.

Maintenance – As most people believe, freshwater tanks are generally easier to care for compared to saltwater tanks. Whereas you’ll have to do general maintenance on your freshwater tank every 2 to 4 weeks, a saltwater tank will require you to maintain it every 1 to 2 weeks.

Size – A big difference between saltwater and freshwater tanks is the size. Generally speaking, saltwater fish need more room than freshwater fish do. This is due to the fact that saltwater cannot hold the same amount of oxygen as freshwater can. Specifically, your saltwater tank would have around 20% less oxygen in it than your freshwater tank would have. Therefore, you need a tank big enough so that it does not run out of oxygen.

Algae growth – Algae growth is a huge difference between freshwater and saltwater tanks. Because freshwater tanks have a larger number of plants in them, they are able to restrict the growth of algae. Saltwater tanks do not have this abundance of plants. Therefore, there tends to be more algae growth in saltwater tanks. To prevent this, you can do frequent water changes to make sure the water is clean and clear of any free-floating algae.

Lighting – The amount of lighting in your tank can result in numerous things. For one, proper lighting in saltwater tanks can be a great way to limit the amount of algae growth. If you have a dimmer light, there tends to be less algae growth. The problem lies where you have extremely bright lighting in a saltwater tank because it will immediately stimulate the growth of algae.

If You Are a Beginner…

Most people think that a beginner should always go with the freshwater tank simply because it is easier to maintain. They think that saltwater tanks are way too difficult for beginners to handle, and this is just false.

With the right methods, a beginner can maintain a saltwater tank just as well as they could a freshwater tank. It is important that you put tons of research behind maintaining a saltwater tank because saltwater tanks are sensitive to changes in water and pH levels.

Therefore, if you are a beginner and want to have a saltwater tank, that’s great! But, it is crucial that you maintain it with care. You must remember to keep an eye on the water at all times to make sure the pH level is not dangerous. Also, keep in mind that saltwater tanks must be cleaned more frequently. However, if you are willing to put in the time and energy in having a saltwater tank, then a beginner shouldn’t have an issue.

Common Freshwater Fish

Goldfish – Goldfish are some of the most popular species of fish among fish owners. They vary in length, but they are smaller as pets because when in captivity, they are not given the space to grow to their full size.

Bettas – Betta fish are most common among smaller tanks. Betta fish are really the only fish that can be kept in a 5-gallon tank and still live a happy and healthy life. They are relatively small in size, as they only grow up to about 3 inches in length. They come in a variety of bright colors.

Discus – Discus is a part of the Cichlid family, and they can grow up to 7 inches in length. For this reason, they are required to be in a tank that is at least 25 gallons in size. Colors and patterns vary from fish to fish.

Neon Tetra – Neon Tetra fish are very small in size, and they prefer to swim in schools. They make great community tank fish as they have a peaceful and friendly energy. However, they are also very playful and energic making them fun to watch.

Zebra Danios – Hence the name, this species of fish are known for its zebra-like stripes. They belong to the minnow family, and they can only grow to about 5 to 7 centimeters in length. That makes them one of the smallest fish that are common among fish owners.

Common Saltwater Fish

Common Clownfish – Because of its appearance in the movie Nemo, this fish has become the most popular fish for saltwater tanks. They have a bright orange color that is specific to this species. They prefer to swim in schools of at least 2 per tank.

Royal Gramma – This species of fish is perfect for beginning fish owners for a multitude of reasons. They are easier to maintain than other saltwater fish, and they generally get along with other fish in community tanks. Also, they have extremely vibrant colors making them beautiful to look at.

Tangs – Tangs are perfect for beginners. They are resilient to different environments, and they are pretty easy to maintain. They come in a variety of vibrant colors including bright sunshine yellow and sky blue. One thing to keep in mind is that they do require at least an 100-gallon tank.

Green Chromis – The Green Chromis fish is the number one imported saltwater fish in the aquarium trade. Their body is a light fluorescent green color that will illuminate the waters in your tank. They prefer to swim in schools of at least 5 of their own species.

Firefish – Firefish are very long and thin. They have a light-colored body with a red or orange-toned tail which gives them their name. Since they are calm and friendly, they are perfect for community tanks. Their favorite things to do are swimming very fast and hiding in rocks and other aquarium features.

Essential Freshwater Aquarium Equipment

  • Fish tank
  • Water filter
  • Substrate (gravel, rocks, sand, etc.)
  • Lighting
  • Water heater
  • Thermometer
  • Air pump
  • Cleaning equipment
  • Live plants

Essential Saltwater Aquarium Equipment

  • Fish tank
  • Water filter
  • Substrate (gravel, rocks, sand, etc.)
  • Lighting
  • Water heater
  • Thermometer
  • Air pump
  • Cleaning equipment
  • Salt mix
  • Hydrometer


  • A misconception that even experienced fish owners have is that you cannot have a saltwater tank under 50 gallons. Nano tanks come in sizes ranging from 10 to 30 gallons and are suitable for saltwater applications. So, don’t let the size of the tank deter you from getting a saltwater tank if that is what you really want. However, in most cases, a saltwater tank will need to be bigger. This is due to the fact that saltwater is not able to hold in as much oxygen as freshwater is able to.
  • A lot of people think that once you choose either a freshwater or saltwater aquarium, you cannot convert it. This is highly untrue. All you need to do is make some critical changes. This includes thoroughly cleaning out the tank completely before switching to avoid any contamination. Also, you have to switch out all of the accessories when you are switching. It may seem difficult and time-consuming, but you are definitely able to convert it.
  • When it comes to saltwater tanks, many fish owners decide to utilize corals. People assume that corals are easy to care for because they remain sort of stagnant in the water. The problem is when people think that the only way to nourish these corals is by light, and this is completely false. It is important that feed your corals some sort of protein in order to keep them happy and healthy. A popular choice of protein for corals is plankton.
  • Since there is such a stigma around how difficult saltwater tanks are to maintain, people tend to think that maintain a freshwater tank is easy. Freshwater tanks have so many factors that you need to look out for. For example, it is very important that you condition the tap water that you use because some of those chemicals can infect the water and kill your fish. Also, with freshwater tanks, you must clean the tank approximately every 2 to 4 weeks. Depending on the size of the tank, this can be a lot of work as well. Just because a saltwater tank does require a lot of maintenance does not mean that a freshwater tank is easy and simple. You have to put in work for both of them.
  • Lots of people are scared to own a saltwater tank because of the maintenance. They make the mistake of thinking that a saltwater tank is ridiculously difficult to clean. In reality, you just have to educate yourself on the best methods to use. People too often make the mistake of not checking up on the water in their saltwater tank. Saltwater tanks all center around the water and the water’s pH levels. Therefore, you should always be testing your water to see when a good time is to clean your saltwater tank. With this method, you will hopefully never have to face a difficult cleaning session again.

The Bottom Line

Everyone is going to have their preference of whether they like saltwater or freshwater tanks better. But, it is up to you to decide based on your preferences. Different applications have their own pros and cons, and neither is better than the other.

After going through the factors of both applications, hopefully you were able to distinguish whether a saltwater or freshwater aquarium is best for you.

Leave a Comment