Unraveling the Mystery of Mustard Gas Betta

icon author linh nguyen

By Linh Nguyen Updated on 27 Apr 2023

The Mustard Gas betta is one of the most popular aquarium fish in the world. Its distinctive multicolored appearance has earned it a dedicated following among breeders and hobbyists alike. Originally developed by player/breeder Jude Als, this unique strain took up to 15 years to be bred and selected for its specific characteristics. The original, they have a green-bodied fish with variegated bands of blue or green, yellow, and black that was later updated with white rims to develop them into four-rimmed butterfly bettas. 

This eye-catching species has been widely admired for its vibrant coloring, which creates an effect that looks like “gas” when viewed from afar. Today, the term Mustard Gas (or “MG”) is used, incorrectly as it was originally, to describe any bicolor that has a green, blue, or steel blue body and yellow or orange fins.

In this blog post, we will explore the history and characteristics of the Mustard Gas betta in greater detail. We will discuss how its unique colors were developed over many years of careful breeding and selection by Jude Als. You will also learn about the various features that make this strain so popular among hobbyists today.

1. What is a Mustard Gas beta fish?

1.1. Origin and History

Since the early 1990s, when many young betta players had not yet been born, breeder Jude Als introduced Mustard Gas (MG). According to his definition, MG fish has a blue body and a tail with three blue-yellow-black (or white) edges. According to the only image we see today, the color rims are not separate but blend together in what Victoria describes as the "gas effect".

It took Jude 13 years to launch this new strain of fish. In 2002, he patented the name “Mustard Gas” so no one is allowed to sell bettas under this name without his consent. One of the breeders who bought fish from Jude was Marianne Lewis, who outcrossed and sold the blue-bodied, yellow-tailed fish under the name MG. Jude reminded her to change the name of the line, so Marianne changed the name of her line to Salamander!

Today, the term "Mustard Gas" (or "MG") is used to describe any bicolor that possesses a green, blue, or steel-blue body and yellow or orange fins. In fact, this particular color combination has been around as long as the Non-Red gene itself because it is relatively easy to breed an iridescent betta with a Non-Red betta and obtain an iridescent bicolor in the second generation.

The original Mustard Gas betta by Jude Als

The original Mustard Gas betta by Jude Als

1.2. Appearance

As described by Jude, the original MG should have a green/blue body with three fins. Its tail is also very distinctive; it is yellow at the base, then light green, and then ends in black or smoky at the outer edge. Thus, the tail has all three colors but the boundaries of the edges blend together rather than being separate. Perhaps it looks like a rising gas, which is why it's called "Mustard Gas".

No one can do except the "inventor" Jude Als what Yellow (with 3 colored borders) like this. Their colors are slightly lighter, while later hybrids are all darker yellows. Rumor has it that it took him 15 years to breed this line of fish.

Later, many people crossed the male fish they bought from him with female fish from outside; over many generations, they obtained yellow- or yellow-tailed fish with two-colored edges, but the edges were separate, not merged. If you look at them, you can't see the "gas rising" effect, but these are still labeled as MG for commercial purposes. Of course, Jude Als objected to this, but in general, it doesn't work. Today, people still call the dark background yellow-tailed bicolor fish MG!

1.3. Female

The female Mustard Gas betta is easily distinguishable from the male of its species. It has an elongated body, which is smaller in size compared to the more heavily built physique of the male fish. In terms of coloration, they are much lighter than their male counterpart, usually sporting a dull yellowish or greyish hue. The fins of both genders are similar in colors, but the dorsal fin of female bettas tend to be shorter and their tails don't have a wider spread.

In terms of temperament, the female MG betta can be described as being calmer and more gentle than its male counterpart. They also appear to be less territorial with other females in comparison to males. The female is typically quite peaceful and enjoys staying hidden in the plants and ornaments it has in its tank. As such, they are more suited to planted tanks with plenty of hiding spots for them to hide away from their surroundings.

A female Mustard Gas betta fish

A female Mustard Gas betta fish

2. Quick facts about Mustard Gas

Here is a quick summary of Mustard Gas betta fish.

NameMustard Gas betta fish.
Species NameBetta splendens.
Lifespan2 to 5 years depending on the specific betta fish species.
Size2 to 4 inches depending on species and gender.
HabitatThe tank of at least 5 gallons with plenty of plants, 6.5 to 7.5 pH.
Temperature75 - 82°F (24 - 28°C).
DietOmnivores need a lot of animal protein and vitamins.
Activity LevelSwimming is very active.
Care LevelNeeds medium or above water quality, and requires medium maintenance.
CompatibilitySuitable for community tanks, however, it should not be kept with other bettas.

3. Overview of Mustard Gas

3.1. Variations

These Mustard Gas colored bettas are available in every line, tail type, body type, and fin style imaginable; from  Halfmoon to Doubletail to Super Delta to Crowntail or even Plakat varieties. Depending on the exact variety of betta, the overall color may vary slightly but will typically remain within the yellows, greens, and blacks of a mustard gas hue.

When viewed under different lighting or even in different water temperatures, the Mustard Gas betta fish may appear to be entirely different colors. This can make them even more interesting and unique, allowing aquarium hobbyists to create a wide variety of beautiful tanks with colorful fish.

A Plakat Mustard Gas betta fish

A Plakat Mustard Gas betta fish

3.2. Size

Mustard Gas betta fish (MG) come in various sizes and lengths, depending on their strain. Halfmoon MG bettas will typically grow to a size of 5 to 6 cm, producing a large tail that arcs over their back in an impressive display. Their bodies are often slender but strong, with the typical bright colors of other bettas that highlight their vibrant fins. Plakat MG bettas will be slightly smaller, usually only 3 - 4 cm when fully grown.

3.3. Lifespan

The lifespan of a Mustard Gas Betta is typically between 2 - 3 years. However, depending on the specific species and with proper care, they can live up to 5 years or longer. These fish are best kept in aquariums that have plenty of room and an adequate amount of hiding spots. A filter should also be used to help keep the water clean and oxygenated.

3.4. The behavior

The Mustard Gas betta is a beautiful fish, with bright yellow and green coloration. It has an active temperament and can often be seen exploring the tank or playing with its reflection in the glass. This fish is particularly hardy and easy to care for, making it a great choice for beginners. 

When interacting with other fish, the MG betta will usually shy away from aggressive species. They prefer more peaceful tankmates such as guppies, platys, danios, and rasboras. When kept alone they are less likely to exhibit aggression towards other fish but may still flare up when protecting their territory. Despite this behavior, they are generally considered friendly fish that enjoy swimming close to the surface and catching insects.

3.5. Prices

The Mustard Gas betta is a rare and expensive breed of fish. It is highly sought after by aquarists around the world, who appreciate its unique coloring and patterning. The selling price for an MG betta can vary greatly depending on the size, age, and quality of the fish. Generally speaking, prices tend to range anywhere from $50 - $100 USD per fish. Due to their rarity and higher cost, they are not always available in pet stores or online sources.

If you are looking to purchase a Mustard Gas Betta, be sure to do your research ahead of time so that you know exactly what you’re getting into. Many sellers will try to overcharge for the fish, so it is important to do your due diligence and make sure you’re getting a fair deal.

A Halfmoon Mustard Gas Betta

A Halfmoon Mustard Gas Betta

4. Care

4.1. Habitat, water quality, and tank setup

Mustard Gas bettas are a beautiful and unique type of fish that can be kept in an aquarium. They require a well-maintained habitat in order to thrive and reach their full potential. 

In order to keep this betta line, the water temperature should be maintained between 75°F (24°C) and 82°F (28°C). The pH level should also remain stable at 6.5-7.0, with some room for fluctuation depending on the species of fish being kept. Additionally, the water quality needs to stay clean and free from toxins like ammonia or nitrites, as these can affect the health of your fish. 

When it comes to setting up an aquarium for your betta, it is important to use a large tank with plenty of space and adequate filtration. A capacity of 5 gallons (18 liters) or more is recommended, with a substrate like sand or gravel to provide the fish with hiding places and plenty of plants to create natural hiding spots. Additionally, you should be sure to include some decorations such as driftwood, rocks, caves, and other items that will stimulate the fish’s natural behavior without causing any harm.

4.2. Food and nutrition

When it comes to feeding Mustard Gas bettas, the key is variety. A balanced diet of quality flakes, pellets, and live foods such as bloodworms or brine shrimp should be provided. This will ensure that your fish is receiving all the essential nutrients for healthy growth and development. Feeding two or three times a day in small amounts can also help prevent overeating and unnecessary waste build-up in the water. If a fasted day is desired, just omit one of these feedings but make sure to resume regular feedings the next day. 

These bettas need access to high-quality proteins and carbs as well as vitamins and minerals. The inclusion of Omega fatty acids is also beneficial for their health, as well as items like daphnia, live brine shrimp, white worms, or other forms of algae. All of these foods can be purchased from pet stores and specialty outlets.

4.3. Maintenance mode for fish tank

Aquarium maintenance is essential to raising Mustard Gas bettas. The aquarium water should be regularly changed and fully replaced, as these fish are very sensitive to even the slightest change in their environment. It is also important to keep the tank clean and free of debris, not just for aesthetic purposes but because debris can clog up filters or other equipment and cause dangerous levels of ammonia or nitrite which can be toxic to your fish. To further ensure a healthy environment, it is also recommended that you use an air stone to increase oxygenation as well as natural light, such as from LED lamps. Finally, because these bettas have long fins that can easily become damaged in a crowded aquarium, frequent trimming may be required. If possible, it is best to avoid overcrowding as this can cause stress and health problems.

5. Diseases

Unfortunately, like any other fish, Mustard Gas bettas can be affected by various diseases and parasites. Common illnesses include Ich (white spot disease), Velvet (Oodinium), fungal infections, bacterial infections, and fin rot.

Prevention is the best way to protect your bettas from these common illnesses. Regularly check your tank for signs of disease or stress in your fish, such as discoloration, irregular swimming patterns, or missing scales. You should also make sure to perform regular water changes and keep the water parameters within the optimal range for bettas. Additionally, avoid overcrowding and overfeeding to reduce the risk of disease in your tank.

It's also important to quarantine any new fish that you introduce into your tank. Quarantining will allow you to observe the fish for several weeks and make sure it's free from illness or parasites before introducing it into your main tank. If possible, look for reputable breeders who can provide healthy fish with good genetics. This will help ensure that your new fish have a better chance of staying healthy and avoiding diseases.

Lastly, always buy high-quality products such as food and vitamins to increase the overall health of your bettas. With proper prevention and care, you can help keep your bettas happy and healthy. Be sure to consult a veterinarian if you have any concerns about the health of your fish.

6. Breeding

Since it was introduced in the 90’s by the creator Jude Als people have tried and tried to figure out what it was and how it was created but with little success. There are many speculations as to what actually went into the making of the original Mustard Gas but nobody seems to have quite figured it out.

I have done a lot of research on the subject and have made what I think is a reasonable guess as to what was used to create the original MG but no one may ever know unless Jude is willing to talk.

Jude has said some things that give clues as to what may have gone into the MG. He says that MG when crossed to another MG will only give MG.

When outcrossed to other colors many have produced only multi-colored fish but have already gotten back the MG pattern and colors in the f2 spawn which leads me to believe that there are no known genes in the Mustard Gas fish but rather very dominant traits that have been worked in over a long period of time, hence the 13 years it took to develop the line. Jude also states that there is no red in the Original MG if there is then you do not have a real MG but an outcross. He has maintained that there was no red used in creating the Mustard Gas color. How can there be any red color when the NR gene is present creating the yellow color? There is one other thing that could suggest that Mustard Gas is actually a new color rather than a mixture of already available colors. Mustard Gas fish seem to be the only color that can produce a true breeding line of purple fish, one of the most sought-after colors. No other breeder has been able to produce a true-breeding color of purples.

Many people taken by the high contrast of the Yellow on Blue have tried to replicate the original Mustard Gas color but have not been able to do so, yet! There are however many look-alikes but none yet match the three bands or the set traits of the original Mustard Gas fish.

The Thai breeders have been successful in creating many different fin types as well as different blue/yellow color patterns, all similar to the MG but not quite right when you look at the original MG and then at the replicas.

One of Marianne’s Salamanders

One of Marianne’s Salamanders

MG HM bred by Lapheng Xiong

MG HM bred by Lapheng Xiong

Mustard Gas BF displaying the white bands rather than the typical black.

Mustard Gas BF displaying the white bands rather than the typical black.

MG CT Mask bred by Phil Ngo

MG CT Mask bred by Phil Ngo

Is Mustard Gas betta suitable for you?

To sum it all up, the Mustard Gas Betta is an excellent choice for those looking to delve deeper into their aquarium hobby. As demonstrated in this post, the combination of blue, black, and yellow on its shimmery scales makes for quite a captivating look. Even for those who are not yet experts in the world of bettas, one can still appreciate such an exquisite creature. With proper care and dedication from its keeper, a Mustard Gas might just be the best companion you’ll ever find! If you tried getting your hands on one already or if you’re planning to do so soon, let me know in the comment below how it all went. I’d love to hear about your experience with this enigmatic fish!

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