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How Many Gouramis In A Fish Tank? (10-75 Gallons)

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When I decided to grow Gouramis, the first question I had was how many could be kept in the same fish tank. Initially, I wasn’t sure what to think because there were so many factors that needed to be considered. However, as time passed, I learned what rules to follow to ensure my fish tank doesn’t get overcrowded.

Each Gourami requires one gallon of water for every inch of its length. For example, 10-gallon tanks can hold up to five Gouramis that are 2 inches long. However, 40-gallon tanks can accommodate merely five Gouramis that are 8 inches in length. Naturally, overcrowded tanks can hold fewer Gouramis.

As we proceed, I will list precisely how many Gouramis you can keep in a fish tank, depending on your tank’s volume and fish’s length. Then, I will share a few tips to help you keep your Gouramis as healthy as possible.

How Many Gouramis Should Be Kept Together?

Gouramis come in a variety of sizes. Some of them are so large that they may overcrowd your tank once they grow to their full size. This is why you need to ensure that you get a tank of the correct size.

Fortunately, if you know the size of your Gourami, identifying a tank of the right size isn’t all that difficult. Gourami fish have an average size of 2 to 8 inches, depending on the type. Some kissing Gouramis are 12 inches long. You also have Chocolate Gouramis that are 1.75 inches long.[1]

However, for the most part, this species typically falls within the 2 to 8-inch range.[2] If you have decided to use the ‘One Inch of Fish Per Gallon’ Rule,[3] this is what you can expect:

Medium-Sized Fish Tanks:

  • 10-Gallon tanks can hold five 2-inches Gouramis and zero 8-inches Gouramis.
  • 15-Gallon tanks can hold seven 2-inches Gouramis and one 8-inches Gouramis.
  • 20-Gallon tanks can hold ten 2-inches Gouramis and one 8-inches Gouramis.
  • 29-Gallon tanks can hold fourteen 2-inches Gouramis and two 8-inches Gouramis.
  • 30-Gallon tanks can hold fifteen 2-inches Gouramis and three 8-inches Gouramis.
  • 36-Gallon tanks can hold eighteen 2-inches Gouramis and four 8-inches Gouramis.

Large-Sized Fish Tanks:

  • 37-Gallon tanks can hold eighteen 2-inches Gouramis and four 8-inches Gouramis.
  • 38-Gallon tanks can hold nineteen 2-inches Gouramis and four 8-inches Gouramis.
  • 40-Gallon tanks can hold twenty 2-inches Gouramis and five 8-inches Gouramis.
  • 50-Gallon tanks can hold twenty-five 2-inches Gouramis and six 8-inches Gouramis.
  • 55-Gallon tanks can hold twenty-seven 2-inches Gouramis and six 8-inches Gouramis.
  • 60-Gallon tanks can hold thirty 2-inches Gouramis and seven 8-inches Gouramis.
  • 75-Gallon tanks can hold thirty-seven 2-inches Gouramis and nine 8-inches Gouramis.

10 Gallons is the minimum size for the smaller Gourami fish. But you need at least 55 gallons for the large creatures (8 to 12 inches). Giant Gourami can grow to an incredible size of 28 inches. If you want to bring one home, you need over 200 gallons to accommodate it.[4] That is the minimum. If you want multiple Giant Gourami fish, you need a massive aquarium.

Because some Gouramis have an aggressive streak, especially when you pair them with other Gouramis, you should avoid overcrowding at all costs. Even though many aquarists believe that you need a minimum of 10 gallons for the smaller fish, you may have to invest in at least 20 gallons for the slightly larger species. 

For every Gourami you add, you need five more gallons to be on the safe side. That doesn’t adhere to the ‘One Inch of Fish Per Gallon’ Rule. But that rule doesn’t account for factors such as the presence of plants, decorations, filters, and heaters.[5] 

You don’t have to abide by the rule strictly. In fact, for medium-sized Gouramis, you are better off going with the ‘One Inch of Fish Per 2 Gallons’ rule. This will give you a little more room to breathe and to make mistakes.

How To Grow Multiple Gouramis In A Single Fish Tank?

Gouramis are not that difficult to care for. But if you want to breed the creatures or possibly prolong their lifespan, you have to create a conducive environment for them. That means the following:

  • Temperature – 77 to 82 degrees F.

To prevent aggressive behavior from your Gouramis, I suggest keeping the temperature stable. Even if it falls within the desired range, consistent fluctuations will stress your fish and make coexistence impossible.

That is why I highly recommend checking the Cobalt Aquatics Neo-Therm Pro Aquarium Heater (link to Amazon), which I also reviewed here. After testing dozens of aquarium heaters, I am confident that this one is the best in terms of quality, ease of use, and cost.

  • Water pH – 6.0 to 8.0.
  • Ammonia – 0 ppm.
  • Nitrates and Nitrites – Below 20 ppm.
  • Hardness – 5 to 20dH.

To measure these, I use the API FRESHWATER MASTER TEST KIT (link to Amazon). I like this one because it lasts for hundreds of measures, and you can use it to test more than one variable at a time. It also seems to be the most accurate on the market.

  • Flow – Low. In the wild, Gouramis live in slow-moving water. You have to replicate this same relaxed flow in their tank. Otherwise, you will induce stress in the creatures.
  • Tank Size – At least 20 Gallons, though the actual size will depend on the type of Gouramis as well as the number you want to keep. Some require 30 gallons, others 55.
  • Oxygen – Because they have a labyrinth organ, Gouramis appreciate oxygen-rich water. Typically, you would meet their needs by installing powerful filters that could sufficiently agitate the water. But that would produce a stronger flow, and they wouldn’t like it. Air stones and air pumps are a better solution.

That is where I usually recommend getting the Hygger Aquarium Air Stone Kit (link to Amazon). I like this one because it is incredibly quiet and works flawlessly. All you have to do is to place it in the middle of your tank, and the device will take care of the rest.

  • Plants – Gouramis require planted tanks. Because they spend a lot of time near the surface, you should get them tall plants. Plants alleviate stress. They provide hiding places. You should also add as many decorations as the tank can accommodate.

Some great examples would be Watersprite, Java Moss, and Hornwort.[6] Also, be sure to get the right size plants because some Gouramis are very big and require tall ones. Either way, try not to stuff your tank too much.

  • Tankmates – Avoid large and aggressive fish like Oscars and African Cichlids. Pair the creatures with Rainbowfish, Tetras, and Angelfish, to mention but a few.[7] If possible, prioritize fish that spend most of their time at the bottom or in the middle. Stay away from fast and active fish. They will aggravate your Gouramis.

What Is The Idea Male-To-Female Gourami Ratio?

You need at least two to three females for every male Gourami. If you have just one female Gourami for every male Gourami, the male might harass the female. And if you have more male Gouramis than females, the males are more likely to fight over the females.

The males are the most problematic because of their territorial attributes. You are better off keeping one male Gourami in a tank. If you want to house multiple male Gouramis, get a large tank. 

Two male Gouramis can live peacefully in an aquatic environment if they have plenty of room to claim their territories without clashing. Female Gouramis are less of an issue. They can tolerate one another. It is much easier to keep multiple female Gouramis than multiple male Gouramis.

Do Gouramis Need To Be In Pairs?

Gouramis can live happily in pairs. Though, it is best to aim for groups of five or more. That being said, it isn’t a good idea to keep multiple males in the same tank. While Gouramis are peaceful towards other fish, they have been known to act aggressively towards one another.

Gouramis are somewhat tricky because the males are territorial. On the whole, Gouramis are peaceful fish. They can harass and kill smaller creatures in the tank.[8] But for the most part, they are peaceful. In fact, they can be pretty shy.

They can coexist with other peaceful fish in the same tank. They are not necessarily schooling fish. You don’t have to keep them in large groups to make them happy. But keeping one Gourami in a tank isn’t a good idea because the loneliness will exacerbate its timidity. It will spend most of its time hiding.[9]

Will Two Male Gouramis Fight?

Two male gouramis will probably fight. Though it is less common, Gouramis will fight with other fish and even their own kind. That is why you should only house one male Gourami in the tank unless you have a large tank with plenty of space for each fish to claim its territory.

Gouramis are not unique in this respect. Most fish have been known to harass and even kill other fish in their tank. It is nothing to be concerned about. But if you want to keep them together, then that is something you should consider. If they keep harassing each other, try adjusting their numbers, as described earlier.

Can You Keep A Single Gourami?

You can keep a single Gourami in a tank, although it is not always advisable. In the wild, Gouramis live in groups. If you cannot replicate this in your tank, your Gourami will be lonely and vulnerable. On the whole, it is best to keep two or more. 

That being said, some people have reported success with single Gouramis. Whenever possible, opt for a bigger tank. And be sure to add as many hiding places as you can accommodate. Also, make sure that the fish is big enough that it isn’t going to be harassed by other creatures in the tank.

What Is The Right Way To Add New Gouramis To A Fish Tank?

It is best to add Gouramis one by one instead of all at once. This will allow you to become familiar with their temperament and characteristics before introducing other Gouramis. It will also give you a chance to quarantine sick fish immediately. And if you plan on adding more than one Gourami, introduce them one by one.

I also suggest acclimatizing new Gouramis. You can easily do that by placing the plastic bag on the surface of the water. Wait for a few minutes. Then gently slide the bag into the tank. Repeat this process with each new fish.

This will allow any excess air to escape and make them feel at ease inside their new environment. It also helps with the transition and prevents abrupt temperature fluctuations.

Do Gouramis Kill Other Fish?

In most cases, Gouramis don’t get aggressive enough to kill their tankmates outright. But they can harass and intimidate them to the point that they stress out. It doesn’t usually take much either. A single act of aggression can cause a lot of stress in a tank.

Fish that Gouramis may kill are usually the small ones. That includes Tetras, Rasboras, Bettas, Guppies, and Zebra Danios, among others. This usually happens in tanks that are overstocked or when their tankmates are already injured or sick.

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Gouramis are hardy and long-lived fish. They are great for beginners and intermediate aquarists. If you happen to be a beginner, start with just one or two Gouramis. As the years go by, a large aquarium will become necessary to accommodate more Gouramis and other fish.

As a rule of thumb, make sure that you keep at least two or three females for every male. Males are the more aggressive ones. And they need their own territory. If you don’t want to deal with territorial disputes, keep just one male Gourami in the tank.

Another thing to consider is the Gouramis length. That will determine the tank size you’ll need. Longer Gouramis can receive preferential treatment in terms of food and other resources. But make sure that the tank is large enough for them to swim around freely.