55 Gallon Fish Tank Guide: Dimensions, Stocking Ideas and More…

A 55 gallon fish tank is just about the perfect tank size. It is not too big, not too small, and holds a surprising amount of different fish. You could keep Dojo Loaches, Goldfish or even Chiclids in there. Most of these tanks are rectangular and meant to sit up on a tall stand. However, there are some cylindrical ones that can fit into the corner of a room.

Are you ready to set up your first 55 gallon aquarium? This complete guide features everything you need to know to set up, maintain and stock a 55 gallon tank.

55 Gallon Fish Tanks Explained

Freshwater 55 Gallon Fish Tank

A 55 gallon fish tank is considered a medium sized aquarium. It is a very popular fish tank size and is often picked by newcomer’s for their first setup. This tank is great for medium sized fish as well as larger numbers of small schooling fish.

A tank like this works well with popular freshwater fish like Goldfish or South American and African Cichlids. It can host many beginner friendly species of saltwater fish as well including Royal Grammas, Damselfish and the ever-popular Clownfish.

Maintenance should not be too difficult and freshwater setups are lower maintenance than saltwater or brackish tanks.

For all of this tank’s benefits the price of this aquarium will be your first real challenge. It is usually around $200 at a minimum and this does not include its equipment and stocking (more on this later).


  1. With a 55 gallon fish tank you can keek most many of the most popular freshwater and saltwater fish, including: Goldfish, Dwarf Angelfish, Tetras and Rainbow Sharks.
  2. This is a very manageable size for most fish keepers. It does not take up too much space and is not difficult to clean and maintain.
  3. It is a very common tank size to find at most retailers and aquarium suppliers so you should not have too much trouble looking for one. If you shop secondhand you may be able to find it at a much more affordable price too.
  4. 55 gallons offers just enough space for beginner aquascapers to practice their craft, but not so much space that the tank becomes crowded with too many plants or decorations.
  5. Finally, a tank this size fits into almost any room in the house or workplace. You can use it as a centerpiece or a conversation starter in the office.

How Much Does This Aquarium Cost?

When budgeting for your new aquarium you should expect to pay $200-$250 for a new tank. However the exact price of your specific aquarium depends on several factors.

If you decide to buy acrylic instead of glass it will cost between $50-$80 more. Because of this aquarists on a tight budget usually go for a glass fish tank. A tank’s shape will also impact the price as any change from the standard rectangular shape leads to a higher price tag (and corner tanks are often the most expensive).

The price is also influenced by where you buy your fish tank. It may be tempting to splurge on a shiny new aquarium but you may be able to find a pre-owned tank for a much better price.

Some tanks are sold in kits that include a heater, filter and even a basic lighting system. These bundles will cost between $50-$80 more. Unless you are buying one of these kits then the price of the tank does not include the equipment (which can add an extra $150-$180 to your price tag).

You will also need to purchase a stand separate from the tank itself. A metal stand costs between $70-$120, and polished wood stands are often over $150.

The price of your aquarium also does not include the price of all of your fish, plants and decorations. All in all, you should expect to pay between $250-$450 for your new fish tank.

55 Gallon Aquarium Dimension

This size aquarium is almost always rectangular however you can occasionally find them in a cylindrical, oblong shape.

A 55 gallon aquarium’s dimensions are 48″x13″x21″ (length x width x height) but every tank’s dimensions will be slightly different. For example corner takes are usually wider than rectangular tanks so they could measure 45″x16″x24″.

Expect an empty 55 gallon fish tank to weigh between 70 and 80 pounds. Once filled with freshwater it can weigh between 625 and 630 pounds. And once filled with saltwater the tank may weigh between 635 and 640 pounds.

What to Consider When Buying This Tank

Plants For 55 Gallon Fish Tank

A 55 gallon fish tank is likely to be someone’s first fish tank. It is important to remember that an aquarium is a long commitment. You should never purchase an aquarium on a whim or as an impulse buy – some aquarium fish can live for over 10 years.

Your first priority should be the amount of space that you have. Before you buy you will need to measure the room of your house that you plan to place the tank in. Make sure that you factor in the dimensions of the tank plus the stand.

Next, you must consider whether to buy a glass or acrylic fish tank. There are upsides and downsides to both of these. Glass is much more affordable and easier to keep clean, but is also less durable than an acrylic tank. Acrylic is more durable and higher quality, but it is more expensive and also fouls up easily and can get cloudy over time.

In addition to the price of the aquarium itself you must also consider the monthly costs of running your tank and the equipment cost. You will need a filter, lighting system, tank lid, and possibly a heater (if you are running a tropical setup).

A 150-275 watt heater for a tank of this size will only cost you about $25 on average. The lid or hood is the second cheapest piece of equipment at $20-$50 for a basic glass canopy. If you want a hood with aquarium lights built in, you can will be paying $40-$60. An internal filter costs about $30-$50, while an external filter can cost between $40-$80.

Factoring in heating, lighting, and filtration, a 55 gallon freshwater tank will cost up to $11 a month to run. A saltwater tank can cost up to $17 a month.

Finally, you must consider the costs of stocking your aquarium. It is highly recommended that you start with freshwater fish if you are on a budget and avoid searching for specialty breeds and fancy color forms. The rarest and most sought after fish can cost over $100. Saltwater fish tend to cost much more than freshwater fish due to the difficulties of breeding and rearing them in an aquarium setting.

Stocking Ideas

Stocking a 55 gallon aquarium is a bit of a double edged sword. On one hand there is plenty of space, but on the other hand it is very easy to overstock. Your safest option is to pick medium sized fish and active small species.

This fish tank can hold Guppies, Tetras, and any other popular Nano fish in much larger numbers. It can also hold up to 3 Dojo Loaches and a small group of Yoyos. If Goldfish are your thing then this tank is large enough to keep any single tailed or fancy Goldfish breed. Oranda, Veiltail, Black Moor and Common Goldfish do very well in this tank size when kept alone or in pairs.

55 gallons is also the minimum tank size for many large Cichlid species (such as Oscars). Paradise, Pearl, Dwarf and Sparkling Gouramis will all fit in this tank size. Groups of Rosy and Tiger Barbs will fit in just fine as well.

If you are looking to keep a saltwater aquarium then try picking out a few Damselfish and Basslets to add to your community. The Royal Gramma is a particularly good choice. Pairs or trios of Dwarf Angelfish can fit in this tank and you can also keep a single Dwarf Angel with a community of compatible fish. The tank will also hold one of the Damselfish’s favorite tank mates: the Clownfish. The Banggai Cardinalfish is another 55 gallon favorite.

In a brackish water tank you can keep a school of Mollies with a single Pufferfish. Figure Eight and Eyespot Puffers are very popular picks.

Any amount of freshwater or saltwater invertebrates will fit in this tank size but it is not recommended for growing corals most corals need at least 75 gallons to grow. Cherry Shrimp, Nerite Snails, Turbo Snails and Fire Shrimp are just a few of the incredible invertebrates you can use to stock this tank.

Setup Ideas

Artificial Reef Tank

Most coral species need at least 75 gallons to grow but this does not mean that you cannot create a colorful reef environment in a smaller space.

The solution is to use live rock. Live rock is a sort of imitation coral made from rocks. It can come in just about any shape or color and is often a fish keeper’s go to when a real reef is not an option. In a live rock reef tank you can keep many of the same beautiful fish as you would be able to keep in a real coral reef.

You could start with a pair of Royal Grammas and add a group of up to 4 Clownfish. You can also add a single Firefish Goby for a splash of color too.

Comet Goldfish Tank

This tank is an excellent size for a single Comet Goldfish or a pair of Common or fancy Goldfish. A cool water temperature is the most important thing to remember. A Comet Goldfish does not need a heater and cannot survive in water temperatures above 75°F.

You could keep them with a Bristlenose Pleco – this friendly critter will clean up the algae and debris in the substrate. You might want to include a few cleaner snails, although this can be risky. Apple Snails are safe but they must be fully grown and safely hidden from your fish. Decorate your Goldfish tank with plenty of green plants including Tape Grass, Cabomba, Hornwort, Anacharis, and Duckweed.

Dojo Loach Hideout

Have you considered making a Dojo hideout? Dojo Loaches are adorable and intelligent freshwater fish that live at the bottom of the tank.

You should layer the bottom with rocky substrate over soft sand (make sure the rocks are completely smooth with no rough or jagged edges). Use large boulders, logs, driftwood and PVC pipes to decorate the tank and provide places for the Loach to hide. Choose strong plants like Java Ferns, Anacharis, and Hornwort. In a 55 gallon tank you will need to keep your Dojo Loach with smaller fish. Try adding a school of White Cloud Mountain Minnows or a group of 5 or 6 Zebra Danios.

How To Set Up A 55 Gallon Fish Tank

Setting Up 55 Gallon Fish Tank

The first thing you need to do after unboxing your aquarium is to clean it and add the substrate. You will need about 60-75 pounds of gravel to fill the bottom. Rinse the substrate thoroughly until your rinse comes out clear and then layer it so that it is between 0.5-1 inch thick at the bottom of your tank. If you are using multiple grain sizes then lay the finest grains down first. Pebbles, cobbles and boulders should be layered in order of size.

Now you need to fill your tank with water. Add dechlorinators to your water if you are planning a freshwater tank, and marine salts for saltwater. After you fill the tank you must check and adjust the pH and hardness until it matches your fish’s requirements.

Set up the heater first so that you can adjust the water temperature as needed. You do not need a heater for temperate and cool water environments. Now you can turn on your filter to begin the tank cycling process. Your tank must be completely cycled before you add any fish or invertebrates.

It will take up to 8 weeks to completely cycle your tank. You can check in on the process and check all of your water parameters to make sure that they are within acceptable ranges. Even trace amounts of ​nitrates can be toxic to many fish and invertebrates.

After you have made sure that your tank is fully cycled, you can begin adding plants, decorations and finally your fish.

All fish and invertebrates must be acclimated to their new aquarium. To do this you can use the floating bag method. Simply float your fish in their plastic bag on the surface of the tank and gradually replace the water in the bag with the water from your tank. Invertebrates can be acclimated by using the drip method. Place them in a container and use a hose to drip water from your tank to the container until they are completely submerged.

Common Problems

The most common issue with a tank this size is overestimating the size. Some fish only fit into 55 gallons when kept on their own or with very small tank mates. Dojo Loaches and Red Tail Sharks are some examples.

When planning out a community tank you must be aware of the appropriate tank sizes for individuals, multiples and communities. For instance, Comet Goldfish need at least 75 gallons to be kept in groups. Make sure that you do not crowd your tank with too many plants or decorations too. Your fish should have wide open spaces to swim without bumping into things. Even for community fish, compatibility can be limited in a tank of this size. Some otherwise peaceful fish (such as Dwarf Angelfish) may turn into big bullies in close quarters.

Another common problem is waste. A 55 gallon community tank generates a lot of waste. Ammonia, nitrates and other waste products can make your fish very ill when allowed to accumulate. There are many different filters that you can use for your aquarium but you must make sure that the one you choose is powerful enough for your specific tank setup. You cannot rely on your filter alone to keep the tank clean.

You will also need to perform a manual water change every 2 to 4 weeks, depending on the needs of your fish. A 25-50% water change refreshes your tank and clears out any nasty waste. When cleaning your tank you must also clean your glass and vacuum your substrate.


There are so many setup options for this aquarium. You can create an underwater jungle, a live-rock reef, or any other aquatic world that you can think of. It is an excellent medium sized tank for beginners and experts alike and it makes a wonderful conversation starter.

The cost of the aquarium may hold you back but there are plenty of ways to invest in one without breaking the bank. If you buy from a secondhand dealer or opt for lower priced materials, you can create a beautiful aquarium even on a low budget.

Whether you are a seasoned fish keeper or just starting out, a 55 gallon tank is a rewarding experience that anybody can enjoy.

Which fish live in your 55 gallon tank? Let us know in the comments section below…