55 Gallon Fish Tank – Overview, Setup, Stocking Ideas

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Setting up your first tank is a lengthy and research-heavy project. Among the first things you need to decide is your aquarium size.

If you’re considering a medium-sized, 55-gallon tank, this article is for you! Keep reading to discover everything you need to know about a 55-gallon aquarium setup.

I’ll cover all the relevant information you need, including tank dimensions, holding capacity, cost, stocking ideas, and a short rundown of the aquarium setup process.

Will a 55-gallon tank fit in your desired location? Is it affordable? What type of fish can you keep in this aquarium? Find out the answer to all your questions below!

55 Gallon Fish Tank Dimensions

So, you’ve decided to choose a tank with a 55-gallon capacity. This is a decent medium-sized aquarium. Not too big, not too large, it can house a good number of fish and tank décor.

But you can have a bit of variation in tank dimensions. Two tanks holding 55 gallons of water won’t necessarily have identical measurements.

For the most part, tanks of different capacities come with standard dimensions. Your average 55-gallon tank will measure 48’’ L x 13’’ W x 20’’ H. These dimensions refer to the glass container only.

They exclude the canopy, which would add additional height. As you can see, the standard tank is quite long, with decent width and height.

These dimensions should work for most setups. But you can also find custom-made tanks that are longer or shorter.

If the standard measurements don’t fit your chosen location or stand, you can always find 55-gallon tanks with different measurements. Other common dimensions include 36’’ L x 18’’ W x 20’’ H, and 55’’ L x 22 W x 14.5’’ H.

55 Gallon Fish Tank Stand

A fish tank stand is a specially designed structure that supports your aquarium and houses aquarium equipment like external filters.

Typically, the stand will look like a double cabinet, but some are as simple as a console table. The stand’s role is to provide stability, support, and even weight distribution for your tank.

A solid stand is a must for large and heavy aquariums (50 gallons and up).

Don’t worry; you can easily find pre-made stands that fit most aquarium sizes, including a 55-gallon tank.

Always check the stand dimensions and holding capacity when looking for a stand for your 55-gallon tank. The stand should hold at least 550 lbs and fit your aquarium measurements.

Besides the stand holding capacity and dimensions, you must also consider the stand material and structure. Most stands are made of either particle board, plywood, or metal.

Particle board stands are susceptible to moisture damage and are not recommended for most aquariums, primarily if you use a sump filter.

Plywood and metal stands are durable, moisture-resistant, and have excellent weight-bearing capabilities.

Finally, we need to discuss the stand structure. Typically, you’ll find two types of stands. First, there are stands with an open top.

They might have either an inner rim or an internal grid for aquarium support. These stands are suited for regular glass tanks.

If you have an acrylic or rimless aquarium, you must provide additional support for even pressure distribution. In that case, you should opt for a closed-top stand with a self-leveling mat.

How Much Does a 55 Gallon Fish Tank Weigh?

Multiple factors can influence the total weight of an aquarium. What material is it made out of? Is it filled to full capacity?

Are there additional components like substrate or decorations? These things can add up to a considerable difference.

Let’s start with the material. The standard 55-gallon glass tank will weigh roughly 80 lbs dry. Just the container itself is surprisingly heavy and might require two people to transport and set up.

The same-size aquarium will weigh 20 lbs dry if made of acrylic.

Then comes the water. Each gallon is the equivalent of 8.34 lbs. If filled to total capacity, you’re looking at an extra 459 lbs on top of the aquarium’s dry weight.

So, a glass tank can weigh up to 539 lbs, while an acrylic tank will weigh 479 lbs.

The tank can be even heavier if you’re planning to create a saltwater setup. On average, saltwater aquariums weigh 8.56 lbs per gallon, or a total of 490-550 lbs when filled.

Adding the substrate, decorations, and equipment will increase the weight further.

How Much Does a 55 Gallon Fish Tank Cost?

The price of a 55-gallon tank can vary depending on a few factors. The material, structure, and additional equipment can considerably bulk the price.

You can expect to pay between $150-$600+ for a brand-new tank, with the average price being $200. For a saltwater setup, expect to pay even more. Here’s a more in-depth look at price factors:

Glass vs. acrylic: Glass tanks are considerably cheaper than acrylic ones. Not only that, but they come with other pros.

Unlike acrylic tanks, glass tanks are scratch-resistant and non-porous, they require less support due to the strong bottom, and they don’t yellow over time.

Braced vs. rimless: Rimless tanks have a neat, modern feel. However, such tanks have lower pressure resistance and require thicker glass and beveled edges.

They also need full bottom support and the use of a self-leveling pad. For all these reasons, a traditional braced aquarium will be safer and cheaper.

Pre-equipped vs. DIY: You can find aquarium sets that include everything you need for your setup.

You get the tank, the canopy, the lights, and even the stand with the same purchase. Unsurprisingly, this will cost you more than a plain aquarium.

You can cut costs by buying tank equipment from different sources, especially if you catch a good sale.

Mixing and matching aquarium equipment also allows you to customize your setup to best suit your needs.

How Many Fish for a 55 Gallon Tank?

How many fish could you keep in your new tank? There’s no one-size-fits-all answer to this question.

It will depend on the fish species, as some are larger than others. Generally, you should allow 1 gallon of water for each 1 inch of fish.

So, if you have a species roughly 4 inches in size, you’ll need to provide 4 gallons of water for each fish.

This means you can keep up to 14 fish of that said species in your tank. Sticking to this rule helps you to stock your aquarium without overcrowding it.

The same rule applies whether you want to mix different fish or create a single-species aquarium.

So, if you keep 5” and 3” fish together, each fish should get 5 and 3 gallons of water, respectively.

55 Gallon Tank Stocking Ideas

The beauty of a 55-gallon tank is that it allows you to keep a decent number of fish and a variety of species, both medium and small.

Of course, you’ll probably deal with the dreaded choice paralysis with so many options available.

A good place to start is to decide what type of aquarium you want. Do you want a freshwater tank, a saltwater tank, or a brackish aquarium? This choice will determine the types of fish you can keep.

Once you’ve decided on your setup, consider some of the following colorful and beginner-friendly species:

Freshwater tank stocking options include:

If you prefer saltwater tanks, consider some of the following colorful species:

  • Goby fish (up to 4 in. long)
  • Cardinalfish (2-8 in. depending on the species)
  • Clownfish (4.3 in.)
  • Butterflyfish (4-8 in.)
  • Wrasses (2-8 in.)
  • Damselfish (2-4 in.)
  • Firefish (2-3 in.)
  • Royal Grammas (3 in.)

Best fish for brackish tanks of 55 gallons:

  • Mollies (up to 4.5 in. long)
  • Violet Dragon Goby (3-5 in.)
  • Archerfish (5-7 in.)
  • Mudskipper (4-11 in. depending on species)
  • Green Spot Puffer (6 in.)

You have plenty of options to create the most interesting and vibrant aquarium. If you want to combine different types of fish, I recommend checking out some of my other articles.

I’ve written extensively about compatible fish species for peaceful community tanks.

You’ll find information about fish with similar water parameters, behavior, and size there.

How to Setup a 55 Gallon Fish Tank?

Setting up a tank means a couple of things. First, you’ll have to equip the tank. Secondly, you must fully cycle your tank to create a hospitable environment for fish and invertebrates.

Finally, you need to decorate and set the proper water parameters. The tools and equipment you’ll need to accomplish these goals differ depending on the aquarium you want.

For Freshwater Aquariums:

  1. Provide adequate filtration

A 55-gallon tank requires a filter with an output of at least 110 gallons. The type of filter you choose doesn’t matter as much.

A hang-on-back or canister filter are both excellent options. Just ensure a good mix of filter media for optimal water filtration. You’ll need a filter sponge and ceramic rings as a bare minimum.

  1. Include an airstone

You need to maintain oxygen concentrations in the water, especially if you’ll have a well-stocked aquarium.

An air stone is a perfect tool to avoid stagnant water and dead zones in the tank.

  1. Add a heater

Most freshwater fish species require temperatures of at least 72°F. Fish are also sensitive to temperature fluctuations, so you must maintain a stable level at all times.

A heater with a built-in thermometer is the perfect way to achieve this.

  1. Choose a substrate

The substrate is an essential element when cycling your tank. It houses a lot of beneficial bacteria to balance the aquarium ecosystem. It also creates a more natural look for your tank.

You have multiple options here, including sand, soil, and gravel. Soil is one of the best choices, especially if you plan to add plants later on.

  1. Prep the water

Once everything is in place, it’s time to fill your tank. Depending on your water source, you might need to use a combination of water conditioners to achieve optimal water values.

A dechlorinator will help you neutralize the chlorine and chloramine in the water. Depending on the fish you plan to keep, you may also need to use either a water softener or hardener.

  1. Cycle your tank

Finally, this is the most important and lengthy step when setting up your tank. Cycling the aquarium will help you maintain stable pH and ammonia levels when introducing your fish. This is crucial to keep your pets healthy.

The easiest way to cycle your tank is by using bottled bacteria products. These products are typically labeled as “biological boosters” and are available in most pet stores.

You’ll also need ammonia and nitrite testing kits to monitor this process.

  1. Add your decorations, plants, and fish

Once the ammonia and nitrite levels drop to 0 ppm, you’re ready to finish your setup. You’ll need to provide hiding spots to prevent stress and bullying between your fish.

Add the plants, driftwood, rocks, and other decorations first. Then, you can begin acclimating your fish to their new home.

For Saltwater Aquariums:

  1. Choose an adequate filtration system

Filtration in saltwater tanks is a little different. Gallon for gallon, such tanks require more powerful filtration than freshwater tanks.

If you want to keep corals, you’ll also need additional equipment. That’s why most marine aquarists opt for sump filters or canister filters.

These filters have higher biological and mechanical media capacity. A sump filter can also house additional filtration equipment that would otherwise clutter the aquarium display.

Depending on how many fish you intend to add, you might also want to invest in a protein skimmer. A protein skimmer removes fish waste and maintains stable water chemistry more efficiently than a filter alone.

Finally, a calcium reactor is also critical if you’re going to set up a reef tank. Corals need a tightly balanced alkalinity level.

The reactor will provide the corals with the calcium they need to consume to grow and stay healthy.

  1. Maintain water flow

Constant water flow and good oxygenation are crucial for saltwater fish and corals. Fish and corals can suffocate and die due to poor gas exchange in the water.

To avoid this, you’ll need to include an air diffuser or air stone in your setup.

  1. Get your refractometer ready

A refractometer is a piece of equipment unique to saltwater aquariums. It helps you closely monitor the salinity level in the water. Refractometers are small, handheld devices.

A refractometer isn’t really part of the setup itself, but it’s still an indispensable tool when keeping a marine tank. You should always have this gadget around during aquarium maintenance.

  1. Don’t forget the heater and thermometer

Saltwater species are more sensitive to temperature fluctuations compared to freshwater fish. Corals, in particular, require a tightly controlled water temperature of around 78°F.

Thus, you’re going to need an aquarium heater and a thermometer. The type or model doesn’t matter much, so you have plenty of liberty here.

  1. Prep the water

You need dechlorinated water to fill your tank. You can use a saltwater tank conditioner or invest in a reverse osmosis system for that. Most importantly, you’ll need to create the correct salinity level for your fish and corals.

To get a specific gravity of 1.025, add 5 cups of reef salt for each gallon of water. Now’s a good time to use the refractometer to measure changes in salinity.

  1. Choose your substrate and decorations

You can choose between various décor options, including driftwood, resin ornaments, saltwater plants, and live rock.

The most important thing to get right is the substrate. This is where freshwater and saltwater aquariums differ.

For your marine aquarium, you should always opt for calcium or aragonite-based substrate.

This helps you maintain proper water alkalinity, which is crucial for reef tanks. Aragonite sand is perhaps the most natural-looking and easiest to find.

  1. Cycle the aquarium

The nitrogen cycle is essential for the health of marine ecosystems. In this regard, freshwater and saltwater aquariums are the same.

Whatever setup you have, you need to cultivate nitrifying bacteria to provide biological filtration against toxic ammonia and nitrites.

Bottled bacteria specifically targeted to saltwater tanks are quick and highly effective in this regard. You can use these and add your fish to the tank 24 hours later.

For the best results, follow the dosing instructions and the steps listed on the product label. Once the ammonia and nitrites read 0 ppm, you’re ready to add your fish to the tank.

Is It OK to Buy a Used 55 Gallon Fish Tank?

New tanks are expensive, especially if we’re talking 50 gallons and up. If you don’t have $200 to spare, it only makes sense to get a used tank for a fraction of the price or even for free.

A used tank can serve you well, but only if you buy one in good condition.

It’s OK to use a second-hand aquarium, as long as you check for the following:

  • Previous glass damage. This includes things like scratches, cracks, and chipped corners or edges. Minor damage is mostly a cosmetic inconvenience. But large cracks or chipping predispose the tank to leakage problems.

Cracks also pose a serious risk to the integrity of the aquarium itself. While a slightly damaged tank is cheaper, you might need to spend extra to fix the damage without guaranteeing long-lasting success.

  • Bracing damage. The bottom and top frames are important structural components in large aquariums.

These help the tank walls withstand the pressure and movement of the water. If the frame is cracked or broken, you might want to buy a different tank.

  • Signs of leakage. If you’re lucky enough to get a live test before buying, this is the perfect opportunity to check for leakage problems. Look for droplets or humid spots across the glass and the outer corners of the aquarium.

Check the stand for signs of water damage too. Do you notice any signs of metal rusting or moldy, uneven wood surfaces? These might be signs of minor but prolonged water leakage. Silicone sealant can also indicate prior leakage problems.

  • Previous water treatments. You need to ask the previous owner about any water treatments and chemical agents used in the aquarium.

This is important because certain fish and invertebrate species are sensitive to certain substances. Snails and corals, in particular, are highly sensitive to fish medication and detergents.

In other words, used tanks are fine, as long as they’re in good condition and not contaminated with harmful chemicals and medication.

The same rules apply to any other second-hand piece of equipment you plan on buying.


A 55-gallon tank is highly versatile and well-suited if you want to keep a diversity of colorful fish.

You can keep a decent number of small and medium-sized species, including Guppies, Bettas, Mollies, Tetras, Barbs, Goldfish, Cichlids, and more!

The standard size for a 55-gallon tank is 48’’ L x 13’’ W x 20’’ H. As for the total weight, a filled 55-gallon aquarium can be anywhere between 479-550 lbs, depending on the material and water salinity level.

Keep these measurements in mind when choosing a fitting aquarium stand.

You can expect to pay an average of $200 for this type of aquarium. While costly, you can find cheaper options. Braced glass aquariums are the most affordable, as are second-hand tanks.

If you buy a used aquarium, ensure there are no signs of damage or leakage.

Author Image Fabian
I’m Fabian, aquarium fish breeder and founder of this website. I’ve been keeping fish, since I was a kid. On this blog, I share a lot of information about the aquarium hobby and various fish species that I like. Please leave a comment if you have any question.
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