If you’ve learned the basics of fish keeping and stepping up from small tanks, like a 15-gallon or 20-gallon, the two tank sizes you might consider are 40 breeders and 55 gallons.
Some say 40 breeders are the way to go because they’re cheap and easier to aquascape. Others say that 55-gallon tanks are better because they offer more space for fish to swim around.
So, which is the better tank size? 40 breeder Vs. 55 gallon? Let’s take a closer look.
40 Breeder Vs. 55 gallon: Dimensions
You may already know the differences between 40 gallons breeders and 55-gallon tanks in dimensions, but here’s a quick recap.
| Tank Size | Dimensions (L x W x H) |
| 40-gallon (breeder) | 36″ x 18″ x 16″ (91cm x 46cm x 41cm) |
| 55-gallon | 48″ x 13″ x 21″ (122cm x 33cm x 53cm) |
Most enthusiasts will advocate for 55-gallon tanks simply because they offer more space to the fish. Large volume certainly is important, but just because they are bigger, does that mean they are a wise choice?
Shorter, wider 40-gallon breeder aquariums do have benefits.
Here’s why.
Extra Water Surface Area
The surface area of the water where gas exchange takes place in the fish tank is thought to be one of the most important factors when it comes to determining the stocking levels.
The extra water surface area provided by a 40b fish tank is actually more beneficial to most fish than the added volume of a 55-gallon aquarium. If an aquarium is overcrowded, the decreased surface area could cause low dissolved oxygen conditions, which can have a big impact.
Extra Bottom Surface Area
Like most cichlids, barbs, corys, and plecos, some fish species require more open surface area to swim on the bottom of their aquarium than others.
These fish spend the most time on the bottom of the tank than in the vertical space, so a large footprint tank gives them more room to explore, establish their territory, and be active.
More Stocking Options
The extra surface areas bring up another advantage – more options for stocking the aquarium with fish.
As a cichlid owner and enthusiast, I would rather sacrifice the extra five inches of vertical height in a 55-gallon fish tank if I can get more surface area.
It can be a big difference not only in stocking African cichlids but for many small South American & Central American cichlids, such as ram cichlid (Mikrogeophagus ramirezi), EBAs, as well as the most popular Gourami.
Well, if your intention is to set up a show tank with tall fish (like a handful of angelfish) or different species that prefer different levels of the water column, 40 breeders might not be the right size for you. A 40 gallons breeder is a great tank, but it does have limits.
Easy to Access
In addition to the limitation on surface areas, another consideration for 55-gallon aquariums is that deep tanks are harder to access.
It is a pain when trying to reach the bottom of the deep tanks and doing routine maintenance like cleaning the glass or gravel vacuuming. This is particularly true when scraping the algae off the glass.
Aquascaping
Aquascaping- designing your dream underwater landscape -is one compelling reason to choose a wider tank, even if you don’t need the extra space for more fish.
Given that a 40-gallon breed tank has a wider viewing panel to show off your aquascaping skills, no matter what type of modern style you are into- Nature Aquarium, IWAGUMI, or Dutch Aquascaping, it definitely is an attractive option for many hobbyists.
In general, the wider the aquarium, the easier to create an eye-catching aquascape.
Easy to Grow Plants
As a general rule of thumb, lower tanks are easier to grow healthy aquatic plants than deep tanks.
The reason is that the light has a harder time penetrating the water column in deeper tanks, making it more difficult for aquarium plants to get the light they need to photosynthesize.
When setting up planted aquariums with easy-to-grow plants, it is advisable to consider 40-gallon breeder aquariums over 55-gallons tanks unless you already have specialty lighting on hand.
40 Breeder Vs. 55 gallon: Weight
One of the most common mistakes made by new aquarium owners is underestimating the weight of the fish tank, especially the final weight when filled with water, substrate, fish, and other decorations.
| Tank Size | Empty Weight | Filled Weight |
| 40-gallon (breeder) | 58 lbs. | 458 lbs. |
| 55-gallon | 78 lbs. | 625 lbs. |
The final weight of a standard 55-gallon glass tank filled with water, substrate, and decorations can easily exceed 625 lbs, while 40-gallon breeders are lighter and typically fall in the 400-500 lbs range. That’s a lot of weight to put on a cabinet that wasn’t designed to support it, and you will need a specialized aquarium stand.
Well, if you plan on placing the aquarium on an upper level floor in your home, 40-gallon breeders are relatively lighter and easier to move around when necessary.
40 Breeder Vs. 55 gallon: Cost
The most significant benefit of a 40-gallon breeder aquarium is the price. It’s considered the best value tank size on the market.
While both 40-gallon breeder and 55-gallon aquariums are standard tank sizes and commonly available during the Petco dollar-per-gallon sale. However, I found the latter often being out of stock, while 40-gallon breeders are always in stock.
Besides the aquarium cost, a 40-gallon fish tank is cheaper to set up and maintain than a 55-gallon tank because of its shorter length and height, meaning you need less equipment.
For example, as I mentioned in my post on 55-gallon aquarium filters, setting up a 55-gallon aquarium requires two HOB filters or sponge filters to prevent “dead spots.”
If you’re trying to keep your costs down, 40-gallon fish tanks are often the best choice since they offer more bang for your buck.
Don’t forget about the aquarium stands, store-bought or DIY; a 40-gallon fish tank stand is going to be cheaper.
40 Breeder Vs. 55 gallon: Which is Better?
The answer to this question is not as simple as it seems. It depends on what your needs and preferences are.
I personally believe that 40-gallon breeders are more versatile, nicer, and easier to work on. However, like most cichlid keepers, my favorite size is the 75-gallon (here is our comparison) because it gives you the big tank look but with added depth from the 40 breeder tanks.
As always, do your research and make sure you’re providing the best possible environment for your fish.