The Do’s and Don’ts of Starting a Beginner Saltwater Tank

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1. Starting a Beginner Saltwater Tank

Starting a saltwater tank might seem intimidating if it’s your first one, but it’s totally doable with research, care, and some patience (especially in the first few months). New saltwater aquarists can start with less expensive, ready-to-use saltwater kits and easier-to-maintain aquariums to develop in the hobby.

One of the most important things to get out of the way first is tank size: Beginners frequently gravitate towards small tanks, thinking they’ll be easier – But this isn’t the case. While they may be more attractive price-wise, smaller tanks fluctuate in parameters, temperature, etc more easily, and are harder to keep stable. The minimum saltwater tank size I recommend for beginners is 40 gallons. This is about the smallest you can go to while remaining both cost-effective, and smart about choosing a tank that will be easier to keep stable.

Once you have more experience, you can always upgrade your tank.

We’ll go over comparisons between freshwater/saltwater, the do’s and don’ts of a beginner saltwater tank, common questions, and more.

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a. Is A Saltwater Aquarium Harder Than A Freshwater One?


Saltwater aquariums are a bit harder compared to freshwater aquariums – Mostly because there’s a little extra equipment, and salinity to keep track of. Freshwater tanks and saltwater tanks are different in terms of cost, level of maintenance, and setups. For example, adding coral introduces additional learning, care, parameters, etc.

It’s worth it for beginners to keep these things in mind; Many starter freshwater aquariums (and freshwater fish) are easier to maintain and more budget-friendly than saltwater ones. Many saltwater fish are very difficult to breed in captivity, and can be more expensive, too.

A bigger tank will help you keep balanced water chemistry in a saltwater fish tank, as the water chemistry in a larger aquarium doesn’t fluctuate as quickly. This can buy beginners crucial time to fix mistakes – Whereas in a smaller tank, the water chemistry changes would rapidly spread, with potentially disastrous consequences.

Despite the differences, saltwater tanks are still doable for beginners – Provided you fully commit to doing the extra research and the extra work, and stick with a larger aquarium. These tanks are truly astonishing and rewarding, and it’s understandable why you’d want one!

Plus, it’s a gateway to reef aquariums, which is an amazing experience and bit of nature to have in your home.

b. Are Saltwater Tanks Good For Beginners?


Here’s the thing: Can a beginner set up a successful saltwater tank? Sure, of course it’s possible with some commitment and research. Is is the most sensible option for beginners? Not really. Saltwater fish are more expensive, and often not as hardy as freshwater ones. Saltwater tank setups cost more (for example, you don’t need a protein skimmer for your freshwater tank!) so this combination means a higher out-of-pocket cost, and possibly a higher risk of failure.

Space can also be an issue; Beginners can get started with a 20 or 30 gallons for a freshwater tank, and still have several species combinations to choose from – But to get started with a saltwater tank, 40 gallons really is the best size for uber-beginners.

That said, once a saltwater aquarium is established, the going gets a little easier. It’s typically the cycling and setup that has the most room for error.

c. What Is The Best Starter Saltwater Tank?


Reef tank

There are lots of great starter kits on the market. Go for one that has all the required equipment, so you get all the essentials in one pack (LED lighting, filter media, tank, and sometimes even a heater). Saltwater kits are a great option for establishing your first saltwater fish tank. Two good options for starters are the Coralife LED Bio Cube Aquarium and Aqueon LED saltwater kit. 

No matter what you buy, do your research to compare the tank’s features and compatibility with the fish species you want to add to the tank. Skip two-stage filtration media and instead go for a three to five-stage filtration system, which will better clean the water.

Most tank kits come with LED lighting onboard, but keep in mind where you’ll place the tank as this can factor in what you purchase; If you’re putting it in a dark corner, you might need extra lighting. Some tanks provide day and night light with the option of timers.

More experienced fishkeepers will be happier skipping the pre-made saltwater tank kits, and instead purchasing components separately, as this allows more detailed customizations according to their preferences.

d. What Size Saltwater Tank Should A Beginner Get?


I recommend a beginner saltwater tank size of 40 gallons. It’s easier to maintain stable water chemistry and water parameters, easier to handle, and is a little more forgiving in terms of leaving if not margin for error, more time to fix it.

Small, nano saltwater aquariums may appear attractive and/or less expensive, but a water chemistry error can turn catastrophic much faster in a low volume of water.

If you’ve had an aquarium before, you’re probably familiar with what an ammonia spike is. If not, listen up: Biowaste, uneaten fish foods, and decaying plants release ammonia into the water. This converts into nitrites and nitrates during the nitrogen cycle. Excess of such compounds can make the tank water toxic for the life present in it and kill your fish overnight. A breakdown of the nitrogen cycle resulting in the sudden presence of ammonia is called an ammonia spike. It’s dreaded among aquarists because it’s deadly.

In the case of an ammonia and/or nitrites/nitrates spike, the large volume of water in larger saltwater aquariums helps dilute the toxic contents – Making water in a larger aquarium more stable and resistant. Hint: These spikes are the top reasons beginners’ fish die.

Given these things, it’s really worth it to go with a 40 gallon saltwater tank if you can. You can always get a different tank size later. Plus, it’s big enough to add reef later if you want!

2. How do you start a saltwater fish tank for beginners? Do’s and Don’ts


Now that we’ve got that out of the way, let’s take a look at the most common saltwater pitfalls for beginners, and how to mitigate them.

a. Do Choose The Right Placement



Submarine Aquarium Photo


This is so easy to overlook. Choose a place where the tank’s temperature can have a good shot at staying balanced, and where it’s easy for you to control the temperature with an aquarium heater. Pick a location with no direct sunlight, as this can increase the growth of algae and make it more difficult to manage the temperature with day/night fluctuations, etc.

b. Do Get The Right Tank Size


We just talked about this, so you’ve got this one in the bag. You’re not going to go for that tiny 15 or 20 gallon tank that’s advertised as a saltwater setup, right? Because you know that that’s going to be harder and riskier – Right? 🙂

Contrary to popular belief, smaller tanks aren’t easier. They’re the opposite. Less water volume means less stable water chemistry. The smallest change can throw the whole tank out of whack, harming the inhabitants. For your initial saltwater tank setup, go with a 40 gallon tank if you can. If you must go smaller, choose 30 or 35 gallons. Remember that you’re also monitoring to keep optimal levels of calcium, magnesium (Mg), salinity, and phosphate (Po4) in a saltwater tank. 

c. Don’t Skip Tank Cycling!


Oh, man. If I had a dollar for every time I read beginner questions on forums about why their fish died overnight when, with a bit of digging, we discover they hadn’t cycled the tank. It’s really sad, and it’s the #1 reason this happens! Beginner aquarium hobbyists MUST learn about the nitrogen cycle and how to cycle a tank.

Preparing the ecosystem of the tank requires plenty of time and patience. This stage of establishing a saltwater tank is known as ‘cycling’. It takes about 4-6 weeks to mature and prepare the water through the nitrogen cycle, although sometimes adding live rock and beneficial bacteria can speed things up a bit. Let’s take a look at this more closely below.


  • Role And Importance Nitrogen Cycle 

Nitrogen cycle graphic


The nitrogen cycle is the process of “biological filtration” that converts ammonia into nitrite and nitrate using beneficial “good” bacteria. This good bacteria begins to grow in the tank’s filter over time, and maturing process of biological filtration is known as ‘cycling’.

Once there is enough to keep ammonia levels at 0 and nitrite and nitrate levels in check, the tank is considered cycled.

A new tank can’t handle livestock because it doesn’t have biological filtration yet.

A new saltwater aquarium requires time to build a mature and stable biological foundation. The production of bacteria in vast numbers is crucial to process organic waste in your fish tank, making it safe for fish and other inhabitants. Without mature biological cycling, the inhabitants of the tank will die.

Don’t rush the maturation of biological cycling and nitrogen cycling of your saltwater tank. This is such a common error. Halfway here is not enough. If you add your fish to a new tank without cycling it, you’re basically putting them in a space where they’ll be slowly poisoned to death. There’s nothing there yet to break down those toxins.

What’s more, once the tank is cycled, don’t dump your fish in all at once! Introduce species one at a time, giving the tank ecosystem time to adapt, and testing the water quality for a couple weeks to make sure the tank can handle it before you add more fish.

d. Do Quarantine, & Don’t Purchase Animals in Poor Health


Sketchy aquarium stores exist, unfortunately. Purchase from a reputable local aquarium store and you’re more likely to get healthy livestock. Observe the fish carefully for signs of illness or parasites before purchase. Bring an experience aquarist with you if you can.

Diseases are also a natural part of freshwater and marine fish. Maintaining water quality will decrease the chances of fish getting sick, but this doesn’t help in the beginning. In the beginning, you have to quarantine all new livestock before introducing them to the tank.

Unhealthy fish put other tank inhabitants at risk. Don’t just dump your new fish in the tank! Purchase one species at a time, keep it in the quarantine tank, and observe them for signs of illness before adding them.

e. Don’t Miss Livestock Incompatibility


Much like quarantining, this is similar to freshwater tanks. Livestock compatibility matters! Do your homework on each species before deciding on your tank configuration, and definitely before purchasing them! Pick species that are well-known to be compatible with each other. Keep in mind that not all saltwater fish are reef-safe, so if you want a reef aquarium, you’ll need to ensure this ahead of time.

f. Don’t Buy Animals Without Knowing Anything About Them


Are you sensing a theme here?! 🙂 In the aquarium hobby, research REALLY matters. Be prepared to be a bit of a book worm, and spending time on forums to make sure you do it right with your new saltwater tank. It might sound like it goes without saying, but know your fish before you buy them. Many people unfortunately “impulse buy” fish in the store because they think they look cool, without actually knowing anything about them or whether or not they can live together. Research is essential for healthy aquarium life.

g. Do Use Quality Saltwater


Saltwater foam


Saltwater aquariums contain salty water. We know this. But how does it get salty? You have a few options to get salt water for your tank: You can mix salt water at home, buy pre-mixed saltwater for pet stores, or even add ocean water to the saltwater tank.

It’s also worth noting here that much like freshwater tanks, tap water can have a significant effect on water chemistry. If you’re using tap water to create your aquarium system, test it ahead of time for lead and metals if you can. Know that some tap water will be harder or softer than others. Many aquarists love using reverse osmosis (RO) for their systems.

Tip: Don’t overfill your tank. Leave some space for the tank decor and tank equipment:)

h. Do Get The Right Equipment


Ah, yes, more research! Know what it is and how it works. If you’re burnt out on reading, go down to your local aquarium store and talk to an experienced aquarist there to learn about marine aquarium equipment.

A keen understanding will make you aware and help you monitor the tanks properly. Do read the instructions that come with your equipment, and understand their role in monitoring and maintaining water chemistry.

  • Heater

Tropical fish are the most common saltwater fish, and water heaters are crucial in saltwater aquariums to maintain accurate water temperature. Do buy adjustable water heaters as this will allow you to adjust the temperature easily.

  • Lighting System

Good lighting is essential for establishing a thriving saltwater aquarium. Hot tip: The ability to REMOVE lighting is also key. Fish don’t have eyelids. They rely on darkness to sleep. If you live in Alaska where you get 22 hours of daylight in the summer, you’ve got to put your tank in a place where you can block out light so your fish can sleep.

Similarly, being able to give them light in the winter is critical.

Do buy a long-lasting, quality lighting system, and don’t let your LED lighting get hot. If you have corals, you’ll need special lighting.

  • Protein Skimmer

A good and effective skimmer helps maintain water quality of the reef aquarium. It captures biowaste by combining water and air in a chamber, which bubbles up deposits of biowaste compounds, which are left behind after the water flows out – Similar to foam on the beach.

  • Water Filter Media 

Just like with freshwater, it’s vital to have a strong filtration system in a saltwater tank. It helps to effectively break down toxic elements and compounds like nitrite and nitrate, and helps to clean the tank water sustainably for the inhabitants.

i. Don’t Stock Quickly or Overcrowd 


Remember how I said before to gradually stock your tank, instead of stocking it with a bunch of fish at once? This is to prevent overcrowding, which creates poor water quality and has negative health impacts on fish. By adding fish a little bit at a time, you can monitor the water quality and avoid a spike in toxic compounds, and overcrowding.

Also, beware of the “1 inch of fish per gallon” guideline. Fish need space according to the needs of individual species’ temperament, bioload, requirements, etc. A 4 inch fish with a high bioload will need more space than the same size fish with a low one.

j. Do Put Your Tank on a Maintenance Schedule



Electronic ph tester


It’s amazing how easily life can become busy and before you know it, a few weeks can go by. This is why it’s SO important to put your tank on a regular maintenance schedule. Mark it off on your calendar, and keep a maintenance log. DON’T skip out on maintenance!

Once your tank is cycled, you’ll still need to do regular partial water changes to remove toxins, just like you would with a freshwater tank.

3. Beginner Saltwater Aquarium Fish

a. Ocellaris Clownfish





Easily the best beginner pick, the much-beloved ocellaris clownfish is one of the easiest saltwater aquarium fish to keep. Their bright coloring, hardy nature, and fun, active personalities make them a no-brainer for both beginner and experienced aquarists alike.

One fun characteristic of this fish is their symbiotic relationship with sea anenomes, where they make their home. Add an anenome to their tank, and watch them move in and make it their own!

b. Threadfin Butterflyfish (Chaetodon auriga)



Threadfin Butterfly Fish


Threadfin butterflyfish are also known as auriga, or cross-stripe butterflyfish. These fish are straightforward to care for, with striking colors and patterns, and the tall, hallmark fin of angelfish.

As they’re a shy fish, they need to be provided with ample hiding spots. They’ll coexist well with other peaceful tank mates. They do need lots of algae, live rock, and supplementation with frozen live foods on a regular basis (daily or weekly, depending on how much algae is in the tank). Be aware that they’re sensitive to water chemistry changes, and do best in well-established habitats. Due to their tall dorsal fin, they’ll also need plenty of vertical height in the tank.

c. Pink Spotted Watchman Goby (Cryptocentrus leptocephalus)



Pink Spotted Goby


I’m a huge sucker for watchman gobies. I think they’re lovely, and entertaining due to their burrowing nature.

The best part about this goby is that they form a symbiotic relationship with some shrimp: The shrimp digs the burrow, and the goby acts as the watchman (hence the name), letting the shrimp know if danger is near. At night, the two settle down in the burrow together, and the goby “opens” and “closes” the burrow at night and in the morning by blocking the entrance with a rock. Amazing, right?

The pink-spotted watchman goby is also sometimes called “Singapore shrimp.” They love sifting the sand substrate to eat small particles of fish food.

They need lots of coral rubbles, plenty of room for swimming, and a sand substrate to enjoy sifting the fish food. Watchman goby rarely show aggressive behavior towards other fish. Keep a tight lid on the tank as gobies can be jumpers!

d. Diamond Watchman Goby (Valenciennea puellaris)



Diamond watchman goby


Like pink spotted watchman goby fish, the diamond watchman gobies love to stir the sand substrate looking for small particles of food. This makes the sand substrate clean as it removes food remains, microfauna, and small organisms – But it can also cause collapse of rock formations if they really go at it, so make sure rocks are secure.

The nature of diamond watchman gobies is peaceful and they don’t typically go after other fish. The exception is when they find similar sand sifters in the tank. It’s best to keep one, or two if they’re a mated pair. They’re a reasonably hardy fish, making them a good beginner option.

4. Beginner Saltwater Aquarium: FAQs

a. How Much Does It Cost To Set Up A Saltwater Fish Tank?


This is really going to depend on the fish, aquarium size, brand, quality, equipment, etc, just like any other purchase. But for a general estimate, you could say anywhere from $500-$1000.

b. Are Clown Fish Good For Beginners?


Yes! Clownfish are GREAT for beginners, and in my opinion, the best choice for a beginner. It’s an ideal fish if you’re new to saltwater or reef tank, as they’re easy to care for, hardy, and entertaining.

c. Are Saltwater Tanks Hard For Beginners?


They’re a little more complex than freshwater tanks, as they have more factors to keep track of. Fish tend to be more expensive, equipment is more expensive, and it can be a little harder in the beginning when establishing the tank. Getting a tank of at least 40 gallons will help, as smaller aquariums are less resistant to water chemistry changes.

d. How Much Does A Clownfish Cost?


The price of a clownfish is usually $10-$20. If the fish is big or rare, its rate will increase ($10 to $100). In addition, the price is also determined by color, size, and type of clownfish.

e. Are Saltwater Tanks Good For Beginners?


I mean, it’s possible for a beginner to start a successful saltwater tank, with enough care and research. But it’s not the most sensible choice, due to cost and complexity. Check out Section 1b for detailed info on this.




Additional Sources/Resources:,to%20measure%20and%20maintain%20them



To say that I’m obsessed with all things saltwater is a bit of an understatement. Aquarium Passion has served freshwater and saltwater aquarium hobbyists for over 10 years, and I'm committed to keeping the information accurate and free. My post-bac certification in Sustainability informs my writing about aquarium conservation efforts. When I'm not writing at AP, I'm out in the ocean or researching weird fish.


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