40 Gallon Fish Tank Dimensions And Tips

40 gallon fish tank

Last updated on June 30th, 2022 at 08:46 am

The 40 gallon fish tank is a great size for hobbyists with limited space and time. It can house up to six small-sized goldfish or four larger varieties such as koi, moorish idol, lionhead carp, etc. The smaller footprint also makes it easier to clean than larger tanks; you won’t have to reach as far to get your hand into all the nooks and crannies.

The smaller size also means it will be easier for you to keep up with water changes since the tank doesn’t need as much filtration or aeration, which frees up more time on a busy schedule for other things such as feeding fish or caring for plants.

A 40 gallon fish tank is an excellent choice for someone who wants to keep their options open and does not want a committed long-term investment. A 40 gallon tank can be used with fresh or salt water, as well as live plants, goldfish, freshwater fish etc.

The small size of the tank makes it easy to move around if need be and it is also less likely to need a filter.

40 gallon fish tank dimensions

40 gallon fish tank


A 40 gallon fish tank is a standard size for many beginner aquarists because of its affordability and functionality. It typically measures about 18 inches long by 12 wide, which makes it just the right size to decorate with live plants on one or both sides while still being able to accommodate an average-sized betta as well as other saltwater or freshwater fish.

A 40 gallon tank is not large enough for most saltwater species, which require more than 100 gallons of water to thrive (a standard size known as a “long”). These tanks are typically available in sizes ranging from 125 to 250 gallons and up.

A 40 gallon aquarium can house some types of larger-sized tropical freshwater fish, such as bluegill or catfish.

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A 40 gallon tank is also sometimes called a “high” because it sits off the ground on four short legs and can have two different heights when set up in a corner of a room depending on whether you want to display the top side (which usually includes the water’s surface) or bottom side.

How big is a 40 gallon fish tank?

A 40 gallon fish tank is about the size of a refrigerator. It measures 36 inches by 18 inches by 24 inches and has a front door with an access panel for feeding your pets and cleaning out dirty water.

The capacity of this type of aquarium varies depending on the filter you buy or choose to install in it, though most hold anywhere from 25 to 250 gallons of water.

The average 40 gallon fish tank has a filter that can handle about two-thirds the capacity or up to 150 gallons for those purchasing an aftermarket filtration system.

With this size aquarium, you’ll need at least one light fixture and heater with thermostat control installed in your fish tank. The average filter is a hang-on model, but you can also purchase submersible pumps to keep your water clean and healthy for your pets.

A 40 gallon aquarium should be placed on a sturdy surface that won’t tip over easily if it’s bumped or knocked into other objects in the room, such as tables and chairs.

Why are 40 gallon tank called breeders?

40 gallon fish tank

A 40 gallon tank is called a breeder because they are typically used to house breeding pairs of fish and larger, more high-maintenance species. They are also referred to as “breeding tanks.”

The tank is a good size for many fish species, but may not be large enough to house larger or more high-maintenance aquatics like sharks.

In the case of tanks used as breeding tanks, they are often filled with plants and caves that can provide cover and rooting spaces in addition to decorative pieces such as driftwood.

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A breeder tank is typically larger than a community or single-species setup, and fish are usually housed in smaller groups.

Breeders often contain driftwood as well to provide a natural look for the aquarium and act as shelters from aggressive species.

How many fish can you put in a 40 gallon breeder?

40 gallon fish tank

A typical 40 gallon breeder tank can only house up to five fish. There are plenty of community aquariums that offer this size, which is perfect for small families and couples with limited space or without the time to care for many pets at once. If you’re looking for a bigger option, consider going with 20 gallons instead!

Is a 40 gallon tank good?

Yes, a 40 gallon tank is good. Generally, these tanks are for beginner aquarists who have lower maintenance requirements, like people with freshwater and saltwater fish-only aquariums. The best thing about this size of the tank (aside from the low cost) is that they’re widely available at pet stores or on Amazon!

Best Place to Buy:

The best place for beginners to buy their first tank is at a pet store like Petco or on Amazon. They’re both great places that will have plenty of options available and knowledgeable staff members who can answer any questions you may have about the equipment they offer. You’ll also be able to pick up any items you need at the same time.