Halfmoon Betta: Fish Caring Tips And Miscellaneous Fun Facts

halfmoon betta
Japanese Fighting Fish is reader-supported. When you purchase through one of our links we may earn an affiliate commission (at no extra cost to you).

Last Updated: August 9, 2023 by Flora Gibbins

The Halfmoon betta is a freshwater fish that traces its origins to the tropical regions of Southeast Asia. Its vibrant colors and fun-sized proportions make it a pet favorite for many aquarium hobbyists.


Even though the Halfmoon betta is not fussy, it’s essential to educate yourself on this species before acquiring them. That will allow you to provide them with a comfortable environment that will enable them to thrive.

Today, I will be taking you through the best practices to care for the Halfmoon betta.

A Brief Overview Of The Halfmoon Betta

Like other members of the betta fish family, the Halfmoon betta also belongs to the Betta genus and the B. splenden fish species.

The Halfmoon betta gets its name from its unique tail fin that spans 180 degrees when fully open, resembling a half-moon. Other than that, this gorgeous fish is betta through and through. This means that it also sports bright colors, ranging from deep blues and bright reds to even shades of purple and orange.

Needless to say, Halfmoon bettas are one of the best choices of aquarium fish if you are looking to add some vibrancy to your aquarium.

These freshwater fish are of tropical variety and prefer a warm aquatic environment for optimal survival.

The Halfmoon betta reaches an average length of three inches when fully grown and has a lifespan of between two and four years. However, as you can imagine, their lifespan almost always depends on proper care practices such as a good diet and conducive water conditions.

Like other betta fish, Halfmoons are also predominantly carnivorous.

A unique aspect of the Halfmoon betta is its ability to breathe air from the water’s surface. 

This is all thanks to the labyrinth organ’s presence that enables the fish to uptake oxygen outside traditional dissolved oxygen in the water. This aspect helps these fish meet high metabolic rate activities, accounting for their hyperactive nature and vibrance.

Their hyperactivity, bright colors, and small sizes are just some of the reasons that make these cuties aquarium staples.

Origin Of The Halfmoon Betta

The Betta fish, more formally known as Betta splendens has been around for millennia. It has its roots in the wild waters of Southeast Asia, specifically in the Mekong basin which stretches through countries like Thailand (formerly Siam), Vietnam, Cambodia, and Laos. its popularity skyrocketed in the 19th Century, thanks to the advent of gambling on fish fights.  This practice was especially rife among the Thai and Malay people who bred male Betta fish for fighting purposes.

The wild ancestors of today’s ornate bettas were quite different in appearance. Characterized by more muted browns or greens and shorter fins, they bore little resemblance to the vibrant and flamboyant bettas popular in aquariums today.

The transformation of the Betta from its natural state to the myriad of spectacular varieties we witness now is the result of centuries of observation and selective breeding. Historically, Siamese royalty were known to keep bettas, not just for their beauty but for their territorial and aggressive nature, often setting up fights between males. Over time, breeding efforts shifted from enhancing their fighting capabilities to augmenting their aesthetic appeal.

It was in the late 20th century that a particular tail type emerged, capturing the attention of Betta enthusiasts worldwide: the Halfmoon. Through meticulous selection of fish exhibiting broader tail spreads, breeders were able to produce bettas whose tails fanned out to a full 180-degree semicircle when flared, resembling the shape of a half moon. The emergence of the Halfmoon Betta was a testament to both the art and science of fish breeding.

The success and popularity of the Halfmoon variety led to further experiments in betta breeding. One notable outcome was the Half Sun Betta, resulting from the crossbreeding between a Halfmoon and a Crowntail. This breed combined the full tail spread of the Halfmoon with the dramatic ray extensions of the Crowntail, illustrating once again the endless possibilities that arise from the careful and imaginative breeding of Betta splendens.

Today, various other in-breeds exist to consistently improve the fish’s ornamental value in the thriving fish commercial pet industry. Some of them include albino and white betta.

Fun Fact: Considered the biggest in the betta species line, this aqua pet has everybody wondering how aquarium keepers maintain its form without any problems! Read about King Betta: Fun Facts About This Fish Royalty & Other Info for more details.

The Halfmoon Betta’s Natural Habitat

As mentioned, the Halfmoon betta is a tropical fish species, doing well in warm climate environments. These tropical fish are adapted to survive in water temperatures ranging from 72°-81° Fahrenheit (26- 28 degrees Celsius).

Despite the relatively warm water environment characterized by low dissolved oxygen, these fighting fish can rise to the water surface to breathe atmospheric air. This feat is made possible by the labyrinth organ that allows them to survive in low-dissolved oxygen tropical waters.

Consequently, the surface breathing ability makes betta fish one of the few species of fish that can survive in shallow water. Nonetheless, despite their hardiness, the Halfmoon betta thrives in fresh, soft water.

Wild Halfmoon betta fish survive on a protein diet. 

These fish prefer to eat from the surface of the water. As you can imagine, floating insect larvae form a convenient meal for these fish. In addition, zooplankton and crustaceans form favorite meals for these fish in the wild waters.

Halfmoon Betta Care Guide

The best way to ensure you offer proper care to your pet Halfmoon betta is to mimic its ideal natural habitat, as that is what they are adapted to.

As such, some of the key factors to consider should include appropriate tank size, tank maintenance, and diet.

Tank Size

Despite its smaller stature, the Halfmoon betta requires a lot of room to be comfortable, at least five gallons per individual.

There are several reasons why Halfmoon bettas require more space than other fish of their size.

For starters, the Halfmoon betta is a little ball of fiery energy, constantly moving around its territory, looking for either prey or a fight! As you can imagine, a fishbowl wouldn’t cut it for this hyperactive fish, as that would mean running into walls constantly. Needless to say, that would make for one unhappy and stressed-out fish.

Secondly, and most importantly, this solitary fish is incredibly protective of its personal space. Therefore, if you plan to put other fish in the same tank as the Halfmoon betta, you’ll need to ensure there is sufficient room for everybody to co-exist comfortably with one another.

Tank Habitat

As mentioned, one of the best ways of making a Halfmoon betta happy is by customizing its tank to mimic its natural environment. Despite being a pet, your Half moon betta still runs on its wild instincts. This means that it will always be looking for places it can use to hide from potential predators, where it can build a bubble nest for spawning, and so forth.

Moreover, this aquarium fish’s intelligent and curious nature means that it requires lots of stimulation from its environment to avoid boredom. 

Therefore, it would only make sense that a betta without such places in its tank would be in a constant state of stress and lethargy, weakening its immune system.

One of the easiest ways of achieving that objective is by placing plants, rocks, and caves in your Halfmoon betta’s tank. You can use both live and plastic plants. Halfmoon bettas do not eat plant material, meaning they don’t really care whether a plant is real or fake. However, consider having at least one floating plant that the male will use to make its bubble nest.

Make sure that the decor you use in your betta fish tank does not contain rough edges to avoid injuring your Halfmoon betta’s beautiful but delicate long flowing fins.

Its common practice to have light installations in aquariums. Lighting allows you to set a proper day-night cycle for your fish, promoting good health. However, the choice of lighting is equally as important.

Halfmoon bettas hate temperature extremes. 

As such, avoid light sources that can heat the water, such as halogen bulbs. These light sources cause fluctuations in water temperature, resulting in temperature shock for the fish.

To avoid that, consider using LED lights since they do not emit heat. In addition, electrical professionals should handle all electrical wiring in the betta tank. This precaution is to avoid the electrocution of the fish due to wrong cabling.

Tank Maintenance

Tank maintenance entails all the activities involved to ensure optimal tank conditions.

Fish waste contains ammonia that can make the tank toxic when left unchecked, leading to diseases. As such, you need a good biological filtration system to regulate ammonia levels in the aquarium.

While you can use plants for that purpose, a biological filter is more effective. That is because a filter not only removes toxic compounds and food remnants from the water, it also performs surface agitation to increase oxygen levels in the water.

A filter also ensures that you do not need to change the tank’s water as regularly.

You should also pay attention to the chemical composition of the water that goes into the aquarium. As mentioned earlier, Halfmoon bettas thrive in soft water. This means ensuring that certain water parameters are met.

Some of the vital water parameters to consider include pH, water hardness, and temperature. Strive to keep the pH neutral (7.0), water hardness levels between 70 and 300ppm, and temperatures between 72°-81° Fahrenheit.

On certain occasions, the water supply to the fish tank may contain chlorides and chloramine compounds. This scenario occurs when there is excessive chlorination of water supplies, typical for municipal water inlets. When these chemical levels build up, the water quality becomes toxic for the Halfmoon betta.

In this case, you should consider using a water conditioner to neutralize the chloride compounds.

Halfmoon Betta Diet

Halfmoon bettas are carnivorous, meaning they derive their nutrition from animal sources. A wild Halfmoon betta diet typically consists of insect larvae, small crustaceans, and zooplankton.

Therefore, to keep things natural, you should also aim to mimic your pet’s wild diet by giving them frozen foods, such as black worms, brine shrimp, ants, and daphnia, among other animal protein sources.

Consider making things interesting for your Halfmoon bettas by placing live brine shrimp inside the tank to provide them with an opportunity to utilize their hunting instincts.

You can also feed commercial fish food to your betta fish. However, ensure it is made of high-quality animal protein and does not contain filler products, such as cereals, that are of no worth to a betta.

Halfmoon bettas have small stomachs. This means that it is easy to overfeed these small fish, which can lead to a host of health problems. It also does not help that Halfmoon bettas are voracious eaters, stuffing themselves silly given half a chance.

As a rule of thumb, you should only feed betta fish once a day. Serve them a portion they can complete in 3 minutes, removing any leftovers once that period is over. This helps minimize food waste in the tank that would affect water quality.

Male Halfmoon Betta Fish vs Female Halfmoon Betta: The Differences

Male Halfmoon Betta
Male Halfmoon Betta
Female Halfmoon Betta
Female Halfmoon Betta

Knowing how to tell male and female bettas apart is essential for safety and breeding purposes. This knowledge will help you prevent unnecessary conflict in the tank due to two incompatible male placements and allow you to select a pair to breed easily.

Fortunately, it is pretty easy to distinguish a male Halfmoon betta from its female counterpart. First off, unlike males, female Halfmoon bettas are less prone to aggressive tendencies. In fact, half moon females can coexist with just about any other species of fish peacefully.

Secondly, half moon bettas are sexually dimorphic, with males sporting brighter colors and long flowing tails. On the other hand, females have duller colors, and their fins are not as impressive as those of males.

Like peacocks, Halfmoon males also use their beauty to woo females.

Stocking Halfmoon Bettas with Other Fish

As mentioned, siamese fighting fish are known for territorial aggression. They will fight to defend their turf and assert their dominance over existing space. Consequently, choosing the ideal tank mates for a Halfmoon male requires some research.

For starters, it should go without saying that you should never stock members of this species together. Halfmoon males will eventually fight each other regardless of how large the tank is. What’s more, they will even attack Halfmoon females. Fortunately, Halfmoon females seem to be more tolerant of one another and other fish species.

While the male Halfmoon doesn’t mind a solitary existence, that does not mean that it cannot coexist with others — it all depends on the attributes of the potential companions. Examples of suitable tank mates for Halfmoon bettas include Harlequin rasboras, female cardinalfish, Ember Tetras, Pygmy, and female Gypsies, to mention a few.

Ideal fish candidates should be less colorful, less hyperactive, less aggressive, and smaller.

It is simpler to couple other colorful fish with a female Halfmoon betta population without risking potential aggression in the tank.

Therefore, before placing other fish species together with the betta fish, it is crucial to consider the abovementioned considerations.

Common Disease and Infections Affecting Halfmoon Bettas

Like other pet fish, Halfmoon bettas are also susceptible to several diseases resulting from parasitic, fungal, and bacterial infections. On most occasions, these infections are caused by less than ideal conditions inside the tank.

One of the best ways to prevent your Halfmoon from contracting diseases is by ensuring the water quality and other vital parameters are always up to par.

Some of the telltale symptoms of a sick Halfmoon betta include:

  • Duller colors
  • Lethargy
  • Clamped fins that inhibit the fish’s typical gliding movements
  • Decreased appetite

Some common diseases afflicting Halfmoon bettas include Fin rot, velvet/ rust, ich/ white spot disease, and even tuberculosis.

Fin Rot

Fin Rot

Fin rot, also called tail rot, is arguably the most common disease affecting bettas. This fish disease is caused by bacterial infection and is characterized by the tearing of the Halfmoon’s fins. It usually begins with small tears on the edges of the betta’s fins, eventually resulting in the loss of the entire fin if left unchecked.

The main culprit behind this bacterial infection is poor water conditions, especially temperatures below 78F, and the buildup of toxic ammonia compounds. This infection is also highly contagious, meaning that it spreads like wildfire in aquariums with a high population density.

With that said, fin rot is more likely to affect fish with a weak immune system; a healthy Halfmoon betta fish should be able to ward off this disease so long as the tank conditions are right. It is also worth noting that stress is one of the leading contributors to compromised immune systems among bettas.

This condition is treatable depending on the severity. In case of minor symptoms, replacing tank water with clean, well-conditioned water will be helpful. You should also consider moving your fish to a bigger tank, as larger tanks are easier to maintain.

In severe cases, consult a licensed professional for guidance.


Velvet or Coral Disease

Velvet, also called Coral Disease, Gold Dust Disease, or simply Rust, is a debilitating infection that causes tremendous pain and stress to Halfmoon bettas. In severe cases, velvet can result in death.

This disease is caused by the Oödinium parasite that typically comes from introducing new fish to the tank without quarantining them first. It can also come with new live plants. As such, remember to disinfect any plant before introducing it to a beta fish tank.

Velvet is characterized by a brown coat that resembles rust or gold dust on the fish’s skin. 

This rust coat results from the Halfmoon betta secreting excess amounts of mucus in a bid to ward off the parasite.

A Halfmoon betta fish suffering from velvet will also keep rubbing against surfaces inside the tank in an attempt to find relief. Consequently, the fish might develop ulcers and lesions on its skin. Other symptoms include lethargy, clamping of fins, and a loss of appetite.

Maintaining proper conditions inside the aquarium will help you prevent this infection. There are also medications for treating Velvet.



Ick, also called ich or White Spot disease, is also prevalent among betta fish. Like velvet, ick is also caused by an external parasite that irritates the Halfmoon’s skin. As a result, the fish behaves as if trying to scratch an itch by rubbing on surfaces inside the tank, hence its name “ich.”

The constant scratching often leads to white spots all over the fish’s body. These white spots are sores. Without immediate recourse, Ich can cause stress, lethargy, loss of appetite, and even death.

Like velvet and fin rot, Ick is also prevalent in tanks with poor water conditions. This disease is also more likely to affect fish with poor immune systems.

Fortunately, malachite green and methylene blue medications are effective at treating this disease. Additionally, since Ich is highly contagious, it would be advisable to move infected fish.

Watch This!

Frequently Asked Questions

Do Halfmoon bettas change color?

Yes. Halfmoon bettas can change the intensity of their pigmentation on specific occasions, such as when looking to mate or when trying to look intimidating.

Is it okay to hand-feed a Halfmoon betta?

Sure thing. You can hand-feed the fish, as long as you do not insist on touching the pet, which might be a trigger for aggressive behavior. This tip is especially so for the male betta pets.

How long can Halfmoon bettas live with correct care?

Wild Halfmoon bettas have an average lifespan of 3 years. They can live for up to 5 years in captivity due to better water conditions.


With their dazzling colors and gorgeous long flowing fins, Halfmoon bettas are among the most striking aquarium fish out there. They are also quite easy to care for, making Halfmoon betta suitable for both beginner and experienced aquarists.

Do you have any questions or remarks on the Halfmoon betta? Please share them with us in the comments section below.