What is a 40 Gallon Breeder Tank And Why People Use It

When people get carried away talking about our hobby, they start calling tanks “40 breeders” assuming everyone knows. To be honest, I didn’t, and had to do some research to find out.

What is a 40 gallon breeder tank?

A 40 gallon breeder aquarium is a fish tank with specific dimensions. Unlike other 40 gallon tanks that have a more rectangular base, breeder tanks have a bottom that’s more square. It’s designed for breeders to easily access their fish due to the lower profile.  

I’ll show you an image that immediately shows the different dimensions of a 40 breeder, a 40 long and a 40 high. You’ll also want to know why anyone would want to buy a 40 breeder, if it’s an option for you and what fish you are able to keep in them. Let’s first check out some of the dimensions!

Dimensions of a 40 Breeder compared to other 40 gallon tanks

Whenever someone is talking about a 40 Breeder, they’re talking about a tank that’s about 16” tall and not that wide. The exact measurements can vary based on what manufacturer you’re looking at. 

As you can see on the image below, the 40 Long and 40 Breeder are equally tall. However, the 40 Breeder is way more convenient when you’re handling fish. Catching fish in a long tank can be a struggle when they’re fast and agile.

Besides these three varieties, there’s also a 40 Cube. All sides of the 40 Cube are around 20 ¾ “ to end up with 40 gallon. 

The lower profile of a 40 gallon breeder tank makes it easy for the fishkeeper to adjust the layout of the aquarium and to handle fish. The ease of catching fish is the reason why these dimensions are called a breeder tank.

Why would you want a 40 Breeder aquarium

There are many benefits of having a 40 Breeder. The low height in combination with the bigger footprint makes it easy to catch fish and handle fry. However, there are many people that own 40 Breeder tanks that never had the intention to breed any fish. That’s because of the other benefits. 

First of all, when looking at the front of the aquarium, the tank’s very deep. You’ve got roughly 18” of space to fill with rocks, plants, wood or ornaments. That’s much more than the average 12” of space you’ve got with “regular” 40 gallon tanks. 

You really can get creative, and the space offers a lot of room for different layers, additional interest or larger rocks or pieces of driftwood.

It’s because of this reason that 40 breeders are popular among aquascapers. Aquascapers are people who create beautiful landscapes underwater (aquarium landscape).

Another group of people that’s very happy with 40 breeder dimensions are turtle keepers. I’ve got two musk turtles myself, and these varieties aren’t the best swimmers. Instead, they prefer to walk on the bottom of the tank and swim up for air occasionally. With a very tall tank, it gets harder for the turtles to swim up, which is the reason why many turtle owners prefer a lower tank height.

5 Different 40 Breeder Stocking Ideas

If you’re interested in potentially buying a 40 gallon breeder tank, you’ll want to know what fish you could keep and breed. There are many options, and the most popular option would be to convert the tank into a community aquarium. 

I’d be a great option, as you have many options and can also grow a lot of live plants. If a community tank would be best for you, I’d recommend reading my list of 15 suitable community tank fish for you to pick from.

If you’re really going to use the tank for breeding, then I’m happy to tell you that the size allows you to really breed lots of different popular aquarium fish. Let’s jump straight into the first popular option to breed in these tanks!

1. Giant Danio

First up is a fish called Giant Danio. They are fish that display beautiful yellow and turquoise stripes and are breedable in a 40 gallon breeder. These fish are egg scatter fish and require fine plants or a spawning mob to induce them to spawn.

Overall a great option and something that you don’t often see. You’ll have to check with your local fish store whether you’re able to buy some of them. Just like with any fish, make sure to do your research beforehand.

2. Corydoras Catfish

School of Bronze corydoras swimming in aquarium tank,Corydoras aeneus

Fish that are super popular in our hobby are corydoras. There are many varieties, and in your 40 Breeder you’re able to breed even some of the larger common varieties. These fish are great to breed, because the female fish is able to stick their eggs to the glass, to plants and to other ornaments. 

If you’re successful with breeding corydoras, I’m 100% sure that your local fish store will be happy to buy them from you. There’s a high demand for these fish, and you’ll surely be able to get a couple of bucks in either store credit or (if you’re really serious and able to provide on a consistent basis) cash.

3. Long Tail Bristlenose Catfish

Fish that are popular and easy to breed are bristlenose catfish, also known as Ancistrus. When the female has laid eggs, the male fish will actually guard them until they have hatched. This means that it’s easy to get these fish to hatch when you’ve provided the right setting for them. 

I’ve personally bred these fish in a dedicated small tube. It’s really a great fish to breed and there’s high demand so your local fish store will be extremely happy when you’ve got these fish and want them to take them off your hand.

4. German Blue Rams

Fish that are a little more difficult to breed but are most definitely worth the effort are German Blue Rams or GBR for short. They display phenomenal colors when a breeding pair is ready for babies. There’s a great video on Youtube where an experienced breeder explains how to get these fish to spawn. I’ll link it right here:

5. Livebearers

Finally the easiest option on this list, but most definitely not the least rewarding, are livebearers. There are many different fish for you to pick from. Great options are guppies, mollies, platies or swordtails. Because of the size of this breeder tank, you’ve got plenty of space for any of them. 

Get a ratio of 3 females for every male fish you get, feed them enough and provide some plants and you’ll quickly get babies. The livebearer parents can be tempted to eat their fry, so make sure you’ve got plenty of hiding spaces to allow the babies to get out of sight.

Then there’s this great video from Aquarium Coop with some more stocking ideas for a 40 gallon breeder. He goes more into the larger fish options for you to keep.

Don’t put these fish in a 40 gallon breeder

While 40 gal is a lot of water that can house a lot of different fish, angelfish are not suitable for these breeder tanks. A 40 High, with a height of on average 20”, is able to house angelfish, but the 16” that the breeder tanks provide will not suffice. The fish will scrape their fins on the substrate, causing injuries and fin rot. 

Where to buy a 40 Breeder aquarium

I’ve you’re uncomfortable buying used or just prefer a clean and brand new tank, you have to check out this tank on Amazon. It’s the absolute perfect breeder tank and one of the most inexpensive (whilst still quality) out there right now. 

40 gallon breeder tanks are popular, so chances are someone in your region is selling theirs. I would check that first, but make sure you look for obvious damage and thoroughly test whether the tank is watertight (preferable somewhere outside or in your garage, and not in your living room next to your television).

Bart Sprenkels

I have been keeping multiple aquariums since I was 18 years old. Just like many of you, I started with two goldfish but quickly learned they were not suitable for aquariums. Later, I switched to a tropical community tank and I also have two pet musk-turtles in a bigger aquarium. You can read more about me here.

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