Category: Gourami
Common Names: Giant Gourami
Scientific Name: Osphronemus goramy
Family: Belontiidae
Minimum Tank Size: 75 Gallons
Care Level: Moderate
Temperament: Peaceful
Max Size: 12 Inches
Temperature: 72-82 F
pH: 6.0-8.0
Tank Level: Middle to Top
Colors: Blue, Orange, Yellow
Diet: Omnivore
Breeding: Difficult
Giant Gourami Species Overview
Giant gouramis are the largest fish in the gouramis species, growing up to 2 feet long in the wild. They’re a popular addition to large tropical fish tanks because of the bold statement they make with their solid color and an unusual lump on their forehead.
Because they can grow so big, giant gouramis are best suited for intermediate to advanced fish keepers. Ensuring you have a large enough tank for them is crucial, given that many vendors sell these fish as babies.
Distinguishing Features
Giant gouramis change patterns, colors, and even shapes as they age. When they’re young, they have a cream or goldish-yellow body with distinct silver to grayish-blue stripes.
But as giant gouramis grow, they mostly lose these stripes.
Most giant gouramis maintain their cream or yellow-colored bodies as adults. But in rarer cases, their color may deepen to black.
That said, you may find people selling giant gouramis in a range of colors on the internet. Don’t support such sellers by purchasing these fish.
Due to the giant gourami’s light-colored scales, vendors take advantage of them by injecting the fish with dye. Such a situation is stressful for fish.
Dying their scales is likely also painful and may shorten their lifespan.
Another distinguishing feature of giant gouramis is that they have flat heads as juveniles. But as these fish age, many of them grow a lump on their forehead, which scientifically goes by the name “nuchal hump.”
Simultaneously, adult giant gouramis start developing thicker chins and lips. Giant gouramis either have pointed or rounded dorsal fins, depending on their gender.
Origins
Giant gouramis hail from the freshwater of Southeast Asia. Some researchers believe that they specifically originate in the Malay Archipelago.
In either case, because of their size, giant gouramis are a food source for people across Southeast Asia.
These fish enjoy living in rivers, streams, swamps, and lakes with deep enough water to accommodate their large size. You’ll even find them in flooded forests during monsoon season.
Giant gouramis congregate in well-vegetated areas, enjoying plants like java moss and java ferns.
In the wild, giant gouramis live in areas with sandy and rocky substrates. They do well in cloudy water in nature, but you shouldn’t mimic a murky environment in their tank, given that this can lead to toxic build-up.
Size
With the word “giant” in its name, it likely comes as little surprise that the giant gourami is a massive fish. In the wild, they can grow up to 2 feet long.
But in captivity, you can expect your giant gourami to remain relatively smaller, ranging from 16 to 18 inches long.
Given that many giant gourami vendors sell these baby fish ranging from 1-3 inches long, this can cause a headache for new fish keepers if they’re unaware of how large giant gouramis can grow.
Unlike popular belief, a small tank size doesn’t have as big of an impact on stopping a fish from growing. So, placing your juvenile giant gourami in a small tank and expecting them to grow to a size compatible with it isn’t okay.
If you’re worried about how large your giant gourami will grow, purchase a male. Females grow significantly longer and girthier than their male counterparts.
Lifespan
Giant gouramis have a relatively short average lifespan for the gourami species, living an average of two to five years in captivity.
You can expect your giant gourami’s lifespan to be even shorter if the fish breeder you bought them from injected them with dye.
Ensuring your giant gourami has access to a tank with ideal water parameters and a stress-free environment is key to maximizing their lifespan.
Genders
Male giant gouramis have a higher chance of developing a nuchal hump than females, although this isn’t a perfect indicator of gender.
Furthermore, females typically have more pronounced, thicker lips than males. One of the tell-tale signs of gender in giant gouramis, though, is looking at their dorsal fins.
Male giant gouramis have a pointed dorsal fin. In contrast, the female’s dorsal fin has a rounder shape.
Females are also significantly bigger and stockier than males. Whereas male giant gouramis have a more stream-lined fish appearance with their body shape, females are rounder.
Temperament
Giant gouramis have a combination of peaceful and aggressive traits, with males always being more aggressive than females.
As juveniles, giant gouramis have feistier tendencies, both towards other fish and those within their own species. As they work to establish their territory, males frequently fight each other.
For this reason, we recommend placing only one male giant gouramis in a tank, ensuring the remainder are females.
Once giant gouramis reach adulthood, their aggressiveness largely subsides, and they mostly keep to themselves. Therefore, it’s typically okay to house other fish after they reach adulthood.
Tank Parameters
If you’re ready to awe visitors to your home with a massive giant gourami aquarium, below are the must-knows of tending to their tank and water setup.
Minimum Tank Size
The minimum tank size for one giant gourami is 200 gallons. If you’re unfamiliar with aquarium sizes, know that this is a massive amount of space in your home that you’ll need to dedicate to your giant gourami.
And that’s assuming that you only have one fish.
The good news is that you can begin with a 30-gallon tank for giant baby gouramis. But since you’ll ultimately need the 200-gallon tank, it’s often best to start with it.
It’s also a significant financial commitment. Aquariums are expensive, making your $40 to $200 giant gourami purchase look cheap compared to the money you’ll need to set up your tank.
Water Parameters
Below are the water parameters that you should arrange for your giant gourami fish to keep them in optimal health.
Temperature
Your giant gouramis will be happy as long as their water temperature is between 68 and 86 degrees Fahrenheit.
The trick is to ensure the water temperature is similar to the air temperature around the tank, though. That’s because giant gouramis have a labyrinth organ, meaning they can use oxygen in the water and air.
So, it can cause a shock to their system if they take a gulp of air that’s a significantly different temperature than their tank water.
pH
Giant gouramis are fairly flexible in the pH range they can tolerate. They can handle a pH between 6.5 and 8.0.
So, whether you have neutral, slightly acidic, or mildly alkaline water, you can expect them to thrive.
Salinity
Unlike most tropical fish, giant gouramis can tolerate a small amount of salinity. That’s likely because, in the wild, monsoon season can mean that they encounter some brackish water.
Your giant gouramis can leave in water with less than 10% salinity. But we don’t recommend putting salt in their water unless you’re trying to boost their immune system or treat a disease.
Tank Setup
Now comes the fun part—arranging your tank so that it’s attractive to both you and your giant gourami. Below are the must-knows for setting up your aquarium.
Substrate
The ideal substrate for giant gouramis is gravel or sand. Unless you have the rarer black-colored gourami variety, choose a dark-colored substrate, as it’ll make your fish’s color stand out more.
Decorations
You don’t need to go overboard on putting decorations in your giant gourami’s tank. Since these fish are so big, they require plenty of open space to swim.
However, placing driftwood, sunken logs, and a few rocks in their tank mimics their natural habitat and is pleasant to look at.
Plants
Giant gouramis love thick vegetation. So, you should place several plants in their tank. Both plants originating from the substrate and floating on the water’s surface are excellent options.
We recommend divvying up your gourami tank so that they have an area where they can hide in plants and another area of sparse vegetation where they can swim freely.
Java moss, Amazon frogbit, and water lettuce are all excellent choices for your giant gourami.
Lighting
Purchasing an aquarium light with a timer is essential for helping your giant gourami maintain a proper sleep schedule.
You keep the light set on dim, though. In the wild, these fish don’t usually have bright sunlight, given that they live in thick vegetation.
Filtration
A robust filtration system is a must for keeping your giant gouramis healthy. Since these fish are so big, they produce lots of waste that can turn into toxins if you’re not proactive.
At the very least, you should purchase a biological and mechanical filter for your tank. However, a chemical filter is also helpful to deter toxic build-up.
Avoid putting filters with bubbles in your giant gourami’s tank, as this isn’t part of their natural habitat.
Heating
You don’t necessarily need a heater for your giant gourami, as long as their tank is in a room with a temperature that remains between 68 and 86 degrees Fahrenheit.
However, using a heater can be helpful to avoid temperature swings that could stress your fish.
Diet
Giant gouramis are omnivores with herbivore leanings.
Therefore, they love a primarily plant-based diet. However, feeding them live food is also important.
Some of the giant gouramis’ favorite foods include:
- Boiled potatoes
- Blanched spinach
- Brine shrimp
- Beef heart
- Bloodworms
It’s also a good idea to supplement their diet with high-quality flake or pellet food.
You should feed your giant gourami once or twice per day. Let them eat all the food they can for three to five minutes.
Then, remove any remaining food. You’ll soon learn to eyeball how much food your fish can eat during that period.
Breeding
Breeding the giant gourami is tricky, given that you need to move them to a massive tank if they live with other fish.
These fish will be ready to mate once they’re around 6 months old and 4-5 inches long. You should offer the male gourami plant fragments so that they can build a nest.
The nest-building process takes seven to 10 days, and the female will proceed to lay up to 3,000 eggs.
At that time, the male will usher the eggs floating at the surface into the nest using his mouth to carry them.
You can remove the female from the tank once she lays her eggs. But you should let the male remain there, as he’ll have the instinct to protect the nest for up to two weeks while the fry (baby fish) grows.
Adrian Pingstone [Public domain]Common Diseases
Unlike some tropical fish, giant gouramis are hardy. Nevertheless, they can experience several diseases if the water conditions are unfavorable or if you introduce an infested fish into their tank.
Some of the most common diseases and illnesses that your giant gourami might have include:
- Fin rot
- Constipation
- Parasites
- Bacterial infections
- Hole in the head disease
Fin rot and bacterial infections most commonly happen from your giant gourami’s tank having water conditions outside the parameters we discussed. Applying an antibiotic to the water and performing several water changes is often necessary.
You can also treat parasites like those caused by velvet disease, white spot disease, or Hexamita (hole in the head disease) with medication. The sooner you catch the problem, the better the chances your giant gouramis will recover.
Constipation can cause a condition called swim bladder disease. While there are many reasons for this aliment, one of the most common is overfeeding your fish.
Giant gouramis are especially susceptible to constipation if you feed them a diet of primarily dry flakes or whole dried food.
Potential Tank Mates
Giant gouramis don’t need tank mates. In fact, they’d prefer to have the tank to themselves.
But if you want to introduce other fish species into your tank, we encourage you to choose fish that are large and non-combative.
Examples of suitable tank mates for giant gouramis include:
- Loricariid catfish
- Blood parrot
- Knifefish
- Oscar
Should you introduce other fish into your giant gouramis’ tank, make sure you purchase a large enough aquarium to accommodate the extra gallons of water those fish require.