You’ve decided to set up a small saltwater tank but have no clue where to begin. As daunting as it might sound, it is a lot easier to do than you might think.

It is worth noting that saltwater aquariums generally cost more than their freshwater aquarium counterparts. However, the wide range of multicolored saltwater fish and mesmerizing corals make it a worthwhile venture.

This guide explores everything you need to know about how to set up a small saltwater tank from scratch, especially if this is your first time doing it. Read on.

orange fishes in tank

1. Decide on the Type of Saltwater Tank You Want to Set Up

Right off the bat, you first need to figure out what kind of saltwater tank you want to install.

On the one hand, you could opt for a fish-only tank which, as the name suggests, is a basic saltwater aquarium that only hosts fish. It is the most inexpensive marine system you can set up and is ideal if all you’re interested in is, well – fish.

Fish-only saltwater tanks come in two varieties: species-specific and community tanks. A species-only tank hosts one specific breed of fish that typically can’t coexist in the same saltwater aquarium with other species. Think of predatory species such as eels, sharks, rays, triggerfish, etc. Community tanks can host various saltwater fish species in a single aquarium, including cleaner fish, Banggai cardinalfish, and firefish goby.

On the other hand, you could opt for a fish-only live rock tank instead. You would essentially have a small saltwater aquarium with fish but introduce live rock.

While it will add more to the price of the tank, it will help break down nitrites and ammonia waste from the saltwater fish into less toxic nitrates. It also adds to the aquarium’s overall visual appeal instead of having a bunch of fish circling in plain water.

Alternatively, if you have a little more wiggle room in your budget, you could opt for a nano reef fish tank. It is likely the first thing that comes to mind when you think of a saltwater aquarium. These reef tanks have a coral reef, besides the fish and live rock you would find in the tanks we’ve looked at so far.


It is worth noting that the presence of reefs can drive up the cost of marine systems and require specialized equipment to maintain the optimal ecosystem for survival. With the right amount of dedication and effort, it is the most beautiful saltwater aquarium you can have, even as a beginner.

2. Identify Your Fish Tank Requirements

Once you’ve figured out the type of small saltwater fish tank you want to set up, you’re ready to proceed to the planning phase. This step involves understanding the different tank options available on the market, their respective prices, and how much space they’ll take up in your home, office, store, or wherever you plan to install it.

You also need to decide on the type of fish you want to keep in the tank and how they will affect the rest of the aquarium. That way, you know what type of saltwater tank to get.

3. Prepare the Fish Tank

As soon as you’ve done a sufficient amount of research and know which aquarium to get, you can go ahead and purchase the tank. Once you do, you need to prepare it for fish. Here’s what you need to do:

Clean It

Even if your saltwater tank is brand new, you should still clean it. Steer clear of using household detergents and soap. These products may leave behind toxic residues that can be harmful to fish and reefs.

We recommend using a natural acrylic and glass cleaner or a wet microfiber cloth to wipe the interior surface of the saltwater tank.

Check for Leaks

Once you’re done cleaning the tank, the next thing you need to do is check it for potential leaks. To do this, simply fill up the aquarium quarter way with water and let it stand for at least two hours. If you identify any leaks, use an aquarium sealant to fix them.

Choose a Safe Spot for It

You should now have a clean, leak-free saltwater tank to work with. Next, you need to identify a suitable spot for it. Remember, once you fill it with water, live rock, reef, and fish, it will be much heavier to move, not to mention the increased likelihood of mishaps.

That said, there are a few things to keep in mind when choosing a suitable place for your small saltwater tank.

For starters, the surface you place it on should be sturdy enough to hold the weight of the aquarium and any associated equipment you might need to install. It also needs to be level to prevent it from tipping over and falling to the ground.

It is always a good idea to purchase an aquarium cabinet stand suited to the specific saltwater tank you’re getting.

4. Choose a Suitable Substrate

This next step involves adding a suitable substrate. Aquarium substrate is the stuff used to line the bottom of the fish tank. You can use it to enhance the aesthetic of your aquarium or promote a healthy habitat for your marine life.

You could opt for natural-looking grayish-brown gravel to match the color of the live plants and driftwood. Alternatively, you could opt for a bright-colored substrate to match a mermaid or castle-themed children’s aquarium.

Before you add the substrate, make sure that you clean it first. A quick rinse will suffice. Then, add a thin layer of gravel and sand along the bottom of the tank first before pouring in the rest.

5. Fill the Tank With Water

Once you’ve added the substrate, it’s time to fill the saltwater tank with water. It is important to note that you should not add water straight from the faucet. At the risk of stating the obvious, a saltwater aquarium requires – saltwater.

The water in question should have first gone through a reverse osmosis process or, at the very least, treated and de-chlorinated. You’ll then need to add a special salt mix which you can purchase at your local pet shop.

Don’t be alarmed if the water becomes cloudy once you fill up the tank. This is normal and happens when the substrate is disturbed. Leave it to stand for a couple of hours. The particles will eventually settle, leaving the water clear once again.

6. Install the Required Equipment

The type of equipment you’ll need to install will depend on the type of small saltwater aquarium you’re setting up. At the bare minimum, you will need lights, a filter, and an aquarium heater. You may also need to install a UV sterilizer, aerator, and protein skimmer to keep your fish in optimal health and ensure the ideal water quality.

The installation process for this equipment is relatively straightforward. Simply refer to the manual that comes with them, and you should have no problem.

aquarium with fish with glowing yellow light lamp on top in dark room

7. Implement the Desired Aesthetics

If you want to add a few decorations to your small saltwater tank, this would be the time to do it. You can opt for a natural aesthetic by incorporating coral, driftwood, and live rock.

If you’re feeling adventurous, you can go all out and install luminous neon-like lights or go for a generic shipwreck look. Let your imagination run free and bring your vision to life.

8. Cycle the Tank

Before you can add the fish, you first need to cycle the aquarium. The idea behind doing this is to increase the population of various bacterial cultures present in the water.

That way, they act as a biological filter to convert ammonia into nitrites and, finally, into nitrates. Cycling the tank ensures that the water is safe for the fish since ammonia and nitrite are particularly toxic to marine life.

9. Add the Fish

Ideally, you should have already picked the fish species (saltwater, not freshwater fish) you want to host in your new saltwater aquarium setup. The fish species you choose should suit the small beginner tank you’re setting up.

As a rule, you should not add all the small fish at a go, or you risk destabilizing the nitrogen levels in the tank and having to repeat the cycling process again.

Remember, fish are highly sensitive creatures that need to acclimatize to their new habitat. Add a few of them to the small tank to begin with, and leave them for at least a week before adding in the next batch.

Start by placing the bag with the small fish in the aquarium and leave it floating there for at least 15 minutes. Then poke a small hole in the bag and leave it there for an additional 45 minutes to let the aquarium water slowly mix in with the fish bag water.

Then, open up the bag and release the fish into the tank. Discard the bag and water afterward. This is a good process to follow during water changes also, so the fish acclimate to the water temperature.

10. Monitor the Fish

Keep a watchful eye on your saltwater aquarium fish for the next 24 hours to make sure they’re healthy.

Look out for any signs of ill health and check that they are eating at the appropriate feeding times. If you intend to add more fish to your small saltwater tank, ensure that you quarantine them first in a separate container before integrating them into the main aquarium.

Bottom Line

Due diligence is key when setting up a small saltwater tank for beginners. Don’t do things impulsively. Even the smallest error can have catastrophic results.

Use the tips in this guide to help point you in the right direction.

In the meantime, are you thinking about setting up a saltwater nano reef? This guide should help.

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