How Many Fish Can You Keep in a 55-gallon Tank?

The number of fish that can be kept in a 55-gallon tank depends on the size and species of the fish, as well as their compatibility. As a general guideline, a well-maintained 55-gallon tank can support approximately 20-25 small fish or 10-15 medium-sized fish. It’s important to research the specific needs and requirements of the fish you plan to keep and ensure that the tank is properly maintained with appropriate filtration, water parameters, and regular water changes.

How Many Fish Can You Keep in a 55-gallon Tank

How Many Fish Can a 55-Gallon Tank Hold?

If you have a 55-gallon tank and are wondering how many fish can fit in it, don’t worry – there are general suggestions to give you an idea! When selecting the type of fish for your tank, you want to make sure that you are not overstocking your aquarium. Calculating how many fish is safe all depends on the size of the fish and how much swimming space they require.

Fish TypeRecommended number of fish per 55-gallon tank
Angelfish2 – 6
Zebra Danios15 – 20
Molly fish15-20
Ember Tetras40-50
Fancy Goldfish3-4
Neon Tetras30 – 35

Fish pairings

If you are looking to stock your 55-gallon tank with fish, it is crucial to understand the types of fish you want to add and how they interact with each other. Different types of fish require different conditions and depending on, for example, whether it is a freshwater or saltwater tank, not all species can survive in it.

Therefore, pairing your fish correctly is immensely important. To make things easier when choosing fish for your 55-gallon tank, here is a list of suitable pairings: Danios with Gouramis; Molly Fish with Ember Tetras; Angelfish with Guppies; Fancy Goldfish by itself. Knowing the type of fish and their behavior makes stocking an aquarium much simpler!


When you decide to get a 55-gallon aquarium tank, it’s important to think about the filtration system. Having a strong and efficient filter is key to keeping your fish healthy and happy.

When selecting a filter, consider one with an adjustable intake flow that can pump out a minimum of 220 GPH.

This type of filter is good because it aerates the water, helping to make sure your fish don’t get sick due to the waste buildup in their living environment.

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The amount of fish you can keep in your aquarium tank is proportional to the amount of waste that will be present in their water – so having the right filtration system in place beforehand is essential!

Rule of thumb

When it comes to stocking your aquarium, the one-inch-per-gallon rule of thumb is a great starting point. This rule states that you should only add one inch of adult fish per gallon of water in your tank. So, if you have a 10-gallon tank, this should translate to either ten 1-inch fish or five 2-inch fish.

Although this serves as an excellent guideline, it shouldn’t be taken as gospel. As the size of the fish increases, it will require more gallons of water to swim and breathe freely; meaning you won’t be able to fit as many larger fish into a given tank volume.

As such, for the exact number of fish you can stock in your 55-gallon tank, you should seek out expert advice from an aquarium specialist or research online for more detailed advice about what types and sizes of fish fit best in your particular setting.

Tanks are different

When it comes to aquariums, not all tanks are created equal. The size of the tank, the type of fish you’re keeping in it, and the environment inside can all have an effect on how many fish you can actually put into a tank.

A 55-gallon tank is no exception. It is recommended to initially add no more than 10 inches of fish to the tank as part of the acclimation process, typically over a period of one month.

During this time, you should use a proper test kit to check levels of ammonia in the water; once the ammonia level hits 0, you can add more fish–this process may take another month as well.

By following this process carefully, you can ensure that your 55-gallon tank will house healthy fish without overcrowding them!

Is A 55-gallon Fish Tank A Good Size?

Considering the size and shape of any tank is an important factors when selecting one for your home or office, the 55-gallon fish tank may be a great choice. Its dimensions are 48″ L x 13″ W x 20″ H, offering a manageable size that can fit in just about any space you have.

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This tank is perfect for beginners because of its manageable size and relative ease of upkeep. Whether you’re keeping freshwater fish, saltwater fish, or even algae eaters, this tank has you covered. Plus, it’s ideal for those who don’t want something too large as their first aquarium setup.

When it comes to finding the perfect aquarium for your home or office, consider opting for the 55-gallon tank to get started!

How to maintain a 55-gallon tank

Maintaining a 55-gallon tank is not as difficult as it may seem. All you need is the right knowledge, equipment, and a bit of dedication.

The first step to maintaining your tank is purchasing one in the correct size, as without this all other efforts will be useless. Once you’ve chosen the perfect 55-gallon tank, it’s time to select the type of fish that would thrive in this environment – taking caution with size, water temperature requirements, and temperaments of the fish species. Lastly, you’ll need to decide on an appropriate filter for your tank based on its purpose and usage.

After your tank has been set up and populated with fish, it’s important to establish a regular maintenance routine to keep everything clean and healthy. A partial water change should be performed every two weeks – removing some dirty water from the tank and replacing it with fresh clean water.

Additionally, you should vacuum the gravel inside your tank along with cleaning off any algae or dirt that has built up on the glass walls – these steps can help ensure your fish have optimal living conditions.

By following these tips, you’ll be well on your way to flourishing in 55 gallons!


How many fish can I keep in a 55-gallon tank?

The number of fish you can keep in a 55-gallon tank depends on various factors such as the size of the fish, their species, and their individual space requirements. As a general guideline, it’s recommended to stock one inch of fish per gallon of water. So, in a 55-gallon tank, you could typically keep around 55 inches of fish, taking into consideration their adult size.

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Can I overcrowd my 55-gallon tank with smaller fish?

While smaller fish may require less space individually, overcrowding a 55-gallon tank with numerous small fish can still lead to water quality issues and stress among the fish. It’s essential to consider the adult size and territorial behaviors of the fish species to ensure they have enough space to thrive.

What if I want to keep larger fish in my 55-gallon tank?

If you intend to keep larger fish, it’s crucial to research their adult size and compatibility with other tank mates. Larger fish may require more space and produce more waste, impacting the tank’s overall ecosystem. Therefore, it’s advisable to keep fewer but appropriately sized fish to maintain a balanced and healthy environment.

Can I use a 55-gallon tank for a community tank setup?

Yes, a 55-gallon tank can be suitable for a community tank setup, but careful planning is necessary. Consider the compatibility of different fish species in terms of size, temperament, and water parameters. Avoid overcrowding and ensure there are hiding places and territories for each fish to minimize stress.

How often should I clean a 55-gallon tank with a specific number of fish?

The frequency of tank maintenance, including cleaning, water changes, and filter maintenance, depends on the number of fish, their size, and feeding habits, among other factors. Generally, a 25-30% water change every two weeks is recommended for a 55-gallon tank with a moderate fish load.

Are there any specific fish species recommended for a 55-gallon tank?

There are many fish species suitable for a 55-gallon tank, including tetras, barbs, rasboras, cichlids (depending on species and compatibility), angelfish, loaches, and some species of catfish. Researching the specific requirements and behaviors of each species is essential to create a harmonious and thriving aquarium community.


Deciding the right number of fish to add to a 55-gallon tank is an important decision that needs careful consideration. You will need to factor in the fish species, size, and swimming abilities when figuring out the number of fish that can be safely housed in an aquarium.

Doing your research before stocking your tank will ensure you end up with a thriving aquatic ecosystem and happy healthy fish!