How to Start a Saltwater Fish Tank

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The beauty of a saltwater fish tank is unlike anything else. A saltwater fish tank will enable you to keep and admire vivid, exotic marine fish like lovely neon goby, graceful firefish, serene blennies, brilliantly coloured tang, and more.

But keeping a saltwater fish tank is not an easy task. Even experienced hobbyists admit that this type of fish tank is difficult to maintain. A rigid maintenance schedule, regular water upkeep, and fish feeding schedules are just a few things you need to consider.
A little experience with freshwater fish tanks and freshwater fish, in general, may help you get started. This is a guide to setting up a saltwater fish tank for the first time and the basics of caring for saltwater fish.

With some time and experience, you can set up and enjoy your very own thriving saltwater fish tank!?

Types of saltwater fish tank

Before you even think about getting fish, you need to decide what type of saltwater fish tank you want to keep.

There are three types of marine tank setup:

Fish-only tanks:

These aquariums will be all about the fish. There will be minimal decoration, maybe just some coral skeletons (not live coral) or fake coral.

This is a great setup. To begin with, there is plenty of hardy fish like tangs, damselfish, and several captive-bred fish, like the iconic clownfish that you can keep in these tanks.

We highly recommend that you begin with a fish-only tank. This is the cheapest tank to maintain and is good for learning the ropes of marine fish-keeping.

FOWLR tanks:

By ‘FOWLR’ we mean ‘fish-only-with-live-rock’ tanks. These tanks have fish and some live rock, which are really pieces of live coral from old coral reefs.

The live rock is occupied by many different life forms like sponges, invertebrate creatures, and nitrifying bacteria. Live rocks look beautiful but also need special attention.?FOWLR tanks are generally not recommended for beginners.

Reef tanks:

These are the most expensive and challenging marine tanks. Reef tanks are all about the corals and other invertebrate marine life: there are often few fish, or even no fish, in a reef tank.

You’ll need to carefully and regularly monitor water conditions, so the sensitive invertebrates survive and thrive. Again, reef tanks are usually not recommended for beginners.

Select a saltwater fish tank

While it is possible, to begin with, a 10-gallon to 30-gallon tank (called nano tanks due to their small size), saltwater fish are used to living in large ocean spaces and, as a general rule, the bigger the fish tank, the better!

Larger tanks are easier to care for because if something goes wrong with maintenance, the larger volume of water can buffer the effects.

It is also recommended that you choose the tank size based on the mature (fully grown) size of the fish you’re planning to keep. Aiming for around 10 gallons for every fish is a good rule of thumb, but always consider your own fish and plan accordingly.

Finally,? If you have to choose between short and wide or tall and narrow, you strongly recommend getting a short and wide tank. Fish will have more space to swim, air exchange will be better, the light will penetrate better, and it will be easier to reach all the way to the bottom during maintenance without having to put on a wetsuit!

Equipment you will need to keep saltwater fish.

There is no end to the equipment you can get for your marine tank! A basic list of the things you will need when starting includes:

  • a light hood
  • lighting
  • a powerhead for water circulation
  • filtration equipment/skimmer
  • heater
  • thermometer
  • saltwater or sea salt mix
  • hydrometer
  • test kits
  • supplements
  • maintenance tools
  • food
  • substrate
  • etc.!


You don’t need a special lighting pick whatever makes the fish look good for a fish-only tank.

However, if you’re putting in live rock, you’ll need power compact lighting or expensive metal halide lighting.

Corals need a type of lighting called actinic lighting.


In addition to a water filtration system, you can get a protein skimmer and sump system that will eliminate dissolved organic compounds, maintain water pH, improve the clarity of the water, keep algae in check, and maximize the oxygen available.

There are many different types of protein skimmers. Adding live rock also helps with filtration, but that will need additional care.


For a fish-only tank, a laminar powerhead with a jet stream and direct flow is fine. However, if you’re putting in coral, you should set up two powerheads across one another at opposing ends of the tank, so the water jet from both meets in the middle. This will create the turbulence that corals need.

As for size, choose powerheads that produce a water turnover of at least 10 to 20 times the size of your tank. For example, in a 100-gallon tank, your powerheads should produce a total turnover of at least 1000 gallons per hour.

Saltwater or salt mix:

You’ll either need to buy pre-mixed saltwater from your pet store or manually mix salt with water and keep it in a large bucket for your water changes.

If you’re mixing your own saltwater, you’ll need to keep the bucket heated with a heater and circulated with a powerhead.

You’ll also need a hydrometer to check salinity (ideally 1.020 to 1.023). Every time you make a water change, you will need to use this saltwater.

Test kits and additives:

You’ll need basic test kits for a fish-only tank for pH, nitrite, nitrate, ammonia, and alkalinity.

For live rock systems, you’ll need to add calcium. If you’re keeping crustaceans, you’ll want to add iodine. There will be other additives you’ll need depending on the type of marine life you’re keeping.

Other maintenance equipment:

This includes buckets of various sizes, a siphon tube for water changes, an algae scraper, nets, replacement parts for your equipment, etc.

Setting up your saltwater fish tank

Now that you’ve got everything together, you’re ready to set up your tank. Place the tank on a stand and make sure it’s level. Leave clearance for equipment cables.

Next, test all your equipment such as the heater, filtration system etc. Fill the tank with fresh water and leave it for two days with the equipment running.

Check for leaks, and make sure the water temperature is within 2 degrees of 26.7 degrees C or 80 degrees F. Empty the tank at the end of two days.

Fill the tank with salt water. Test it with the hydrometer.

Add substrate. This could be sand, gravel, crushed coral or shells, or even peat. The substrate will contain good bacteria to create the ideal tank environment.

Run the tank for two to three days without fish to ensure the temperature, water clarity, pH, nitrate, nitrite, ammonia, and other water parameters are ideal. The system is cycling properly.

Cycling refers to bacteria working to maintain the right levels of gases in the system. You want the ammonia and nitrites to come down to zero before you’re ready to put in fish. Your test kit will tell you what you need to do. You’ll need patience during this time as you wait for the perfect cycling to kick in anywhere between 5 days to a couple of weeks, depending on the substrate you’ve put in.

Finally, you can add fish. Ideally, add two or three first, and then add the rest. It would help if you started with hardy fish that are easy to care for rather than species that don’t have a high success rate in captivity. You’ll be less likely to abandon your first tank if you lose fewer fish on your first attempt.

Unfortunately, there will likely be a few deaths, as you learn. Make sure to learn as much as you can about the fish you’re interested in. The next section will help you!

Caring for saltwater fish: the basics

Learning what saltwater fish to choose for your tank and how to care for them is a big part of the beginner experience.

It’s good to learn as much as you can about marine life and different varieties of fish. Additional knowledge can be helpful in the future when you may think about upgrading or expanding your fish tank.

Since this is a starter experience, there is no need to make things more difficult by choosing fish that are difficult to care for. We list some good starter fish below.

You may think that since saltwater fish come out of the ocean, they all care for the same. This is not true because some fish are from cooler, deeper waters while others are from reef environments. It is best not to mix these different types of saltwater fish to avoid different tank requirements. Fish that come from the same ocean area are more likely to get along, creating a hospitable aquarium environment.

Choosing the right fish for your tank involves more than just their temperament. You need to consider factors such as space requirements,?how easy they will be to feed, the size and hardiness of the fish, and how much they will cost. As a general rule, keep in mind that saltwater fish are sensitive to tank changes. Stability is key when caring for your fish.

What saltwater fish are good for beginners?

So, how do you go about choosing fish for your saltwater tank? Well, like most things, there is more to it than you may think!

There are many factors to consider to determine what fish are good for beginners. These include space requirements, hardiness, feeding attributes, compatibility, and price. Let’s look at this in more detail:

Space requirements

As beginners tend to have smaller tanks, it is wise to choose starter fish that need less space. It would help if you considered the behaviours of the fish and their adult size when figuring out space requirements.

Feeding requirements

Saltwater fish need more food than freshwater fish. Unfortunately, saltwater fish tend to be incredibly picky when it comes to eating because they are not accustomed to eating food that isn’t live.

Avoid choosing fish that need live food, as they are not ideal for beginners.


One of the most important factors in setting up your saltwater fish tank is the compatibility of the fish. In other words, the fish must get along with the other fish in the tank.

Aggressive, bigger species will more than likely prey on smaller fish. Also, two males of the same species may spar with one another. Any species of fish can get aggressive if they do not have enough space in the saltwater tank. Keep these things in mind when thinking about compatibility and choosing your fish.


If price is an issue, focus more on the tank and the equipment rather than getting lots of fish. You can purchase one or two fish for now and consider more later, especially if you are getting a bigger tank.

Saltwater fish are usually more expensive than freshwater fish, so keep this in mind when choosing your fish.


It’s a good idea to choose saltwater fish that are hardy and adapt well to water temperature changes and quality changes.

Since you are a beginner to this hobby, you will likely have a trial and error experience for one or more fish. That being said, hardy fish will be able to stand changing conditions a little more easily while starting.

Adult size

When choosing your saltwater fish, keep in mind that they will grow up to be adult fish. This means that they will get bigger, maybe a lot bigger, depending on the species.

Choose fish that will thrive in your tank when they are adult-sized and not just when they are super small.

Good saltwater fish for beginners


They will eat pretty much anything, so they’re not picky eaters! But they need lots of hiding spots in the tank.


Though they tend to be aggressive to other fish, they are hardy and easy to care for.


A good beginner’s choice, damselfish are inexpensive and small. They come in all kinds of bright cool colors. They can be aggressive, though.


Another great fish for beginners saltwater fish tanks; gobies are small and inexpensive.

Learn more about saltwater fish

Before you begin taking on the hobby of having a saltwater fish tank, be sure to do your research.

It’s wise to read as much as you can about saltwater fish tanks and/or watch videos online about them.

Everything from water chemistry and proper setup to choosing the right fish and tank can all make or break your saltwater fish tank experience.

It can seem overwhelming at first. But it’s not true that beginners have to start with freshwater fish – with enough preparation,?you can start with a saltwater tank as the first step in your fish-keeping hobby.

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