Halfmoon Betta Guide: Care, Diet, Tank Mates (With Pictures)

Halfmoon bettas are a popular type of betta fish defined by their half-moonshaped tail. If you’re thinking about keeping a half moon betta in your tank then you’ve found the right article! In this article, you will find out everything there is to know including what they look like, how to care for them and how to know if they’re happy or not!

So keep reading to find out everything you need to know!

About Halfmoon Bettas

The Halfmoon betta is distinguished by its long, rounded tail that expands to a 180-degree semi-circle when the fish is flaring its tail and fins for display or in distress. Not naturally found amongst wild betta, Halfmoon bettas exist in many different colors and patterns, including Mustard Gas and Samurai.

The bright colors, varied shape, relatively low cost, and easy maintenance of the halfmoon betta all make them an attractive choice for home aquariums. Despite a reputation for aggression, with the right care and attention, they can make great community fish.

History And Origins Of Bettas

Betta fish were initially collected from the wild and bred to increase their aggression, being used as subjects in gambling matches, similar to dogfighting or cockfighting.

Wild betta fish will fight only for minutes before one fish retreats. The heightened aggression bred into domestic betta means that they can fight for longer, and death is more likely. Winners are determined by the fish’s willingness to continue fighting.

The popularity of betta fights apparently attracted the attention of the King Rama III of Siam (1788-1851), who began to collect fighting fish himself. King Rama III later reportedly gifted several betta fish to the Danish scientist Theodore Cantor.

Bettas began to appear in France, Germany, and other European aquaria towards the end of the 19th century and were soon a popular ornamental fish variety. It appears that they first entered the USA and Australia in the early 20th century.

Today, their popularity in home aquaria means that bettas are abundant in captivity. In the wild, habitat destruction and pollution mean that Betta splendens are categorized by the IUCN as vulnerable.

What Do Halfmoon Bettas Look Like?

In the 20th century, some betta breeders began to move away from breeding purely for aggression and selecting instead for color, pattern, shape, and other ornamental qualities. The colorful and shapely Halfmoon betta we know today emerged from these modern breeding movements in the 1980s. Halfmoon bettas are available in all betta colors.  

Wild bettas normally show strong color only when disturbed or agitated, but breeders have made coloration permanent. A wide variety of hues breed true, with offspring always displaying the colors of their parents.


As with bettas in general, male Halfmoon bettas generally have brighter colors and distinctive fins. Varying color patterns can also be found in male Halfmoon bettas.

Betta colors arise from layers of pigment in their skin as well as the refraction of light within a layer of translucent cells. Moving from deepest layers to surface, pigment or color layers are red, yellow, black, iridescent blue/green, and a layer giving a metallic appearance. The colors from these combine to give a wide variety of betta fish colors, including amongst Halfmoon bettas.


Female Halfmoon bettas do not possess the long flowing tails and fins of the males and are normally more subdued in color with simpler features, although still appearing in a variety of colors.

How Do You Care For A Halfmoon Betta?

The care of Halfmoon bettas is just the same as other bettas, but you should pay particular attention to the size and shape of your fish and adjust recommendations to fit your own fish.

Make sure you’re keeping halfmoon bettas in a filtered and heated tank that’s 5 gallons in size or bigger, provide them the proper diet of betta pellets and live food, and keep the tank planted and decorated so they don’t get bored.


Getting the tank right for your Halfmoon is crucial. Water temperature, pH (acidity or alkalinity), and filtration are all important. The pH should be as close to neutral as possible, and the temperature should be as close to 78°F. Ammonia and nitrite should be at 0PPM and nitrates below 20ppm.

(Here’s how to keep the ammonia levels low in your halfmoons tank.)

As well as keeping the water quality high it’s also important to remember that halfmoons are intelligent and curious fish that require stimulation from their environment to avoid boredom, lethargy, and a weakened immune system.

Wild bettas spend much of their time hiding to avoid predators. Placing plants, rocks, caves, and other ornaments in your fish tank can simulate the natural environment, creating hiding places and helping your Halfmoon betta feel more secure.

(Check out some of the best decorations you can add to your bettas tank!)

Similarly, a well-planned and stocked tank will help cater to the betta’s instinct to claim territory, possibly focused around a particular plant or rocky cave. (You can also include driftwood and Indian Almond Leaves in your bettas tank as well!)

Make sure that any rocks, plants, etc.. have smooth textures and edges to avoid any damage to the delicate fins and tails of your Halfmoon bettas. And lastly, Floating plants can also be a great area for your betta to build bubble nests for breeding.  

(If your halfmoons fins look a bit tattered, find out whether it’s just fin loss or something more serious.)

Lastly a blue or white aquarium LED light with an inbuilt timer can help set a daily routine for your Halfmoon betta, simulating day and night in the wild.

(Find out how important light is to your betta fish.)

Tank Size

The smallest tank you can keep a halfmoon betta in is 5 gallons. However, bigger is always better. If you planned on keeping your halfmoon in a community tank, then it will need to be 10 gallons or bigger.

(Find out why 5 gallons is the minimum size, as well as the best 5 gallon tank for betta fish!)

Diet And Feeding

When you’re feeding your halfmoon, make sure he’s getting a good mix of high quality betta pellets as well as lots of live food he can hunt as well. Daphnia is the best live food for bettas, however, brine shrimp and mosquito larvae are also great choices!

(Click here: if you want the ideal feeding guide for bettas! or find out about all the different types of live food your betta will absolutely love!)

Managing Aggression

Bettas are highly territorial, and Halfmoon bettas are know exception. If you’re putting halfmoons in a community tank make sure the tank is big enough. Even if you plan on keeping a sorority of halfmoon bettas, the females will still need plenty of space!

Without enough tank, space to establish separate territories, or provision of some means of escape, then your bettas will become stressed which could increase the risk of disease.

Males even respond aggressively to the sight of their own reflection, which will also stress them out.

Water Parameters For Halfmoons (In-depth)

Low water quality can make bettas and other tropical fish liable to depression and disease. For maximum health, growth, and lifespan in your Halfmoon betta, you should adjust the water parameters to suit their needs.   


Halfmoon betta’s are tropical fish and need a water temperature between 24–28 °C (76–82 °F). They can survive in temperatures slightly outside this range, however, it’s going to be extremely harmful to them.

Installing a reliable heater in your betta’s tank will ensure that water temperature is maintained in the ideal range. Extreme temperature swings in your bettas tank can be fatal to bettas, as they may end up suffering from temperature shock.

(Find out more about the temperature your betta needs, and why heaters are so important for them.)


The pH level of the water will also affect your Halfmoon betta. The ideal pH is a neutral level of 7.0. However, they can handle a slightly more acidic pH of 6.5 as long as the pH isn’t constantly fluctuating.

Water Hardness

Bettas prefer soft water similar to their natural environment. They can tolerate a wide range of General Hardness (GH), between 5 – 20 DH or 70-300 ppm, but very hard water is harmful.

Adding Indian Almond Leaves, alder cones, or demineralized or distilled water to your tank will all lower water hardness naturally.

(Read this article if you want to find out more about the perfect water conditions for your betta.)

Ammonia, Nitrites, Nitrates

One way or another, your fish tank needs to provide sufficient biological filtration to support your fish. Biological filtration establishes a regular cycling of your tank, breaking down waste (ammonia) and converting it first into nitrites, then down to nitrates. This keeps the water safe for your fish.

While it may be possible to provide the right amount of biological filtration without the use of an artificial filter (e.g., with sufficient live aquatic plants, thorough cleaning, and regular water changes), it’s still incredibly risky.

The filter in your bettas tank will remove debris and toxins (ammonia etc..), help to oxygenate the water through surface agitation, and provide a place for beneficial bacteria to grow. A fully cycled tank will have enough established bacteria to convert ammonia into nitrates after 24 hours but can take around a month to reach this level.

Adding a good quality water conditioner to your tank can also help to remove chloramine, chlorine, and other water contaminants which are bad for fish. I love API Stress Coat which also contains an aloe vera mixture to replace a fish’s slime coat. 

What Diet Should A Halfmoon Betta Have?

Bettas are naturally carnivorous. In the wild, they feed on insect larvae, zooplankton, and small crustaceans, etc. Your Halfmoon should therefore be fed mostly on animal proteins, whether flakes, pellets, or frozen foods. So a long with high quality betta pellets a healthy diet should also include: daphnia, black worms, brine shrimp, mosquito larvae and other small insects.

When choosing foods, do note that betta fish have short digestive tracts which are not adapted for the consumption of cereals (e.g., wheat, corn), often used as filler in commercial fish food. And of course being carnivores, halfmoon bettas cannot be fed plant material.

As a general rule, you should feed a betta at least once each day, providing only as much food as they can eat in 3–5 minutes (A general rule of thumb is 1-2 mini betta pellets twice a day). Remove all leftover food after the feeding period.

Overfeeding could cause health problems, including obesity, constipation, and swim bladder disease. Too much food in the tank can also contaminate the water.

As a little interesting fact, bettas have been known to survive for two weeks without eating, but this is not ideal. After a stressful event (e.g., a move to a new tank or complete water change), it may be normal for your Halfmoon betta to have no appetite for a day or two.

(If you are going on vacation and you’re worrying about how to feed your betta, here are some great ways!)

How Can You Tell Your Halfmoon Betta Is Happy And Healthy

The best way to know if your Halfmoon betta is happy and healthy is to spend time watching them daily and making notes of any changes.


A healthy Halfmoon betta will have a bright, vibrant color.

 Physical Appearance

On top of beautiful coloring, a healthy betta’s should look flawless, healthy scales, no injuries and not ragged. On top of this their tails should be flowing and free, not drooping, ragged or tattered.

(If you notice that the fins appear tattered, then your betta may be suffering from fin rot.)


Healthy halfmoons will also move in smooth, gliding movements. If they are slower than usual, twitching or rubbing against objects, something might be wrong.

In cases where they’re rubbing against things they could be suffering from a parasite like ich, columnaris, or anchor worms.

Likewise, if you notice your betta swimming erratically, there could be a whole bunch of reasons behind why this is happening, such as problems with the water, ammonia levels, or even other fish in the tank.

(Find out some of the most common behaviors that occur in bettas before death.)


If your Halfmoon betta loses its appetite for more than a day or two, then there is a strong chance it could be ill or stressed. Remember the majority of bettas are extremely gutty, so if you notice your betta not eating, then there could be a problem.


Lastly, if you notice that your betta is constantly hiding, then that’s another sign that they’re unhappy. You’ll need to look for what could be stress them and fixing it as soon as possible!

(If you’re interested, here are the best signs to see if your betta is happy or not.)

betta care facebook group

Halfmoon Betta Lifespan & How To Improve Their Lifespan

Halfmoon bettas will live between 3-5 years when looked after. Factors that can improve their lifespan include diet, tank size, water quality, tank mates, genetics, and the state you found them in. However, even sick halfmoons can be cured and go on to live a long life!


A richly varied protein-based diet will give your Halfmoon betta the nutrition they needs for a long lifespan. Make sure you avoid giving them plant matter, and that you’re not feeding them too much, which could cause a whole range of illnesses.

A Large Tank

Making sure you keep your halfmoon betta in a big enough tank is one of the best things you can do for their survival. 5 gallons is the minimum tank size, however, even at this size fluctuations in the water can happen easily which will stress your betta out.

In bigger tanks, even when the temperature drops or there’s an ammonia build up it will have a more diluted affect than smaller tanks. So keeping your halfmoon in a bigger tank is also vital for increasing their lifespan

 Good Water Water Quality

A good quality tank filter, live plants, regular removal of debris and waste, and use of water conditioner will ensure clean, are all essential for keeping your halfmoon betta healthy and improving their longevity!

What Size Tank Do Halfmoon Bettas Need?

No fish should be kept in a tank that is smaller than 5 gallons, and halfmoon bettas are no exception. So make sure you’re keeping your betta in a 5 gallon tank or bigger, with plenty of live plants, a filter, heater and good water quality!

What Are Common Diseases That Affect Halfmoon Bettas?

All tropical fish living in captivity are susceptible to certain diseases which may arise from bacterial, fungal, or parasitic infections. Illnesses are far more common in fish living with poor water quality and lower temperatures than recommended, both of which can weaken the fish’s immune system.

The four most common betta diseases are dropsy, white spot, velvet, and fin rot, and swim bladder disease. Apart from dropsy, all can be successfully treated.


Dropsy occurs when your halfmoon’s body begins to swell because of infection or injury. The body fills with more and more fluids bloating your betta, and causing his scales to stick out the wrong way (like a pinecone)

It normally occurs in old bettas, or bettas that have been raised in poor water conditions.

Treatment has the greatest chance of success when started early, however, the prognosis is never good.

To treat dropsy in your halfmoon betta start by moving him to a quarantine tank with 25% of the tanks old water as well as 75% clean water. Once you’ve done this consider adding aquarium salt one tablespoon for every 3 gallons.

Remember to always mix aquarium salt with a small amount of tank water before adding it to your tank, and make sure you’re changing your aquariums water every 4 days, so the aquarium salt doesn’t build up.

However, remember, prevention is always better than cure, so avoid dropsy by monitoring and caring for your fish appropriately. If your Halfmoon betta’s immune system is compromised by low tank temperature, poor water conditions, or some other stress factor, they may develop dropsy.  

White Spot

White spot, also known as ‘ick’ or ‘ich’ is caused by the external parasite Ichthyophthirius multifiliis, which latches onto fish and makes their skin itchy and uncomfortable. The key visible symptoms are white spots or sores where a fish has attempted to rub affected skin on objects for relief.

When suffering from white spot, your Halfmoon betta may become lethargic, even more reclusive, lose appetite, clamp their fins, and even have breathing difficulties.

The parasite which causes white spot is present in most aquariums but does not affect healthy fish whose immune systems are strong enough to fight it off.

There are several treatment options for white spot involving changing the temperature and salinity in the tank, moving the fish to a different tank until the parasite dies, and treating your halfmoon with medication containing methylene blue or malachite green.  

(Here’s everything you need to know about all the causes and treatments for ich in your betta.)

An example of white spot in bettas:ong>


Also known as Rust, Gold Dust Disease, velvet makes your fish look like it is covered in gold dust or rust. It is caused by the Oödinium parasite, and the gold coating is a result of your fish producing excess mucus in order to fight the infection.

In the early stages of velvet, you may observe your Halfmoon betta twitching and rubbing itself on objects in an attempt to relieve irritation. They will also become lethargic and lose their appetite.

In the later stages of the disease, your fish’s eyes may bulge and cloud over, there may be visible lesions or ulcers on their skin, and they may clamp their fins close to their body. (Make sure you’re not dealing with popeye or cloudy eye.)

You can treat velvet using similar temperature, salinity, and medication regimens to those for white spot but tailored to target the Oödinium parasite.  

Risk factors for velvet include lowered immune system, old tank water, and adding new fish or to your tank without quarantining them for four weeks first. New plants could also carry the parasite and should be thoroughly disinfected before being placed in the tank.   

(Here’s a complete and comprehensive guide on how you can deal with velvet in your halfmoon betta.)

An example of velvet in bettas:


Fin Rot

Fin rot or tail rot is the most common infection amongst betta fish. It’s normally caused by a gram-negative bacterial infection (e.g., Pseudomonas fluorescens) or fungal infection and will affect stressed fish with compromised immune systems rather than healthy fish. With timely treatment, the prognosis is good, and full recovery is likely.

In bettas, fin rot is generally caused by poor water conditions, with tank water being too cold (under 78F), cloudy, and contaminated with old food particles and feces. All of which can raise ammonia, nitrite, and nitrate levels.

Overcrowding caused by too many fish in one tank will also rapidly reduce water quality and lead to fin rot.

Another underlying cause may be inconsistent feeding, with overfeeding or underfeeding damaging immune health.

Symptoms of fin rot vary across mild to severe stages, starting with brownish or jagged fin edges and white tips or spots, and progressing to red, inflamed, or bloody fin bases, or even complete loss of fin and fin membrane.

Fin rot should not be confused with tail biting and fin nipping injuries or snags from rough tank decorations. Rips and tears will not normally have brown or black edges and will not be associated with other symptoms of disease. (Just remember some breeds of betta fish like the double tail Halfmoon are bred to have split fins.)  

The treatment you’ll need for fin rot in your halfmoon depends on how severe it is. In mild cases, it will be as simple as changing the water regularly and improving their diet. More severe cases will require aquarium salt and medication.

(Fin rot should never be left untreated, but this article will show you exactly how you can treat fin rot in your bettas!)

An example of fin rot in bettas:

How Do You Breed Halfmoon Bettas?

Natural aggression means that Halfmoon betta fish can be challenging to breed. So breeding should always be undertaken with caution and supervision.

Bettas are bubble-nesting fish where males are responsible for building nests of bubbles, courting females, defending their territory around the bubble nest, and caring for the eggs and hatchlings.

Betta bubble nests are constructed from saliva-coated air bubbles. During the bubble nest phase, male aggression toward females is lowered as they attempt to attract potential mates.

Males express interest in a female by flaring their gills, spreading their fins, and twisting their bodies. Receptive females respond by darkening in color and developing lines known as “breeding stripes”. In spawning, the male betta wraps his body around the female in a “nuptial embrace” until the female has released all her eggs, which the male will cover in milt (seminal fluid).

At this point, the male will chase the female from his territory to prevent her from eating the eggs. In an aquarium situation, the female should be removed from the tank to prevent injury or death.

(Here’s everything you need to know about how to breed your betta fish.)

What Tank Mates Can Live With Halfmoon Bettas

Although male bettas are normally solitary and aggressive towards one another, they can still inhabit a tank with many types of fish if there is adequate space and suitable hiding places. Broadly speaking, tankmates for your Halfmoon betta must be tropical fish, communal, nonterritorial, and possess a different body type without long flowing fins.

Female bettas are less aggressive and territorial than males, generally making them suitable tankmates for a wider variety of fish. They can also tolerate larger or more numerous tankmates. Male and female bettas should not be kept together, except temporarily for breeding purposes.

Potential tankmates should generally be put in the tank before your Halfmoon betta so that they can establish their territory beforehand and avoid competing with the betta.

Coldwater fish (e.g., goldfish) are incompatible tankmates for betta fish due to different water temperature requirements. Aggressive or predatory fish should be avoided as they are likely to nip the betta’s fins or damage their slime coat. Brightly-colored fish with large fins, especially if smaller and slower (e.g., male guppies), are also unsuitable, as they may be attacked by the male betta.

Compatibility with tankmates will also vary with the temperament of your particular Halfmoon betta, whether male or female. You should carefully supervise the betta’s interaction with any other fish, especially in the early days of sharing a tank.

Great tank mates for your halfmoon betta include: corydoras catfish, tetras, rasboras, platies, mollies, loaches, shrimp, snails, and even African dwarf frogs!


While some tetras are going to be good for your halfmoon betta, some will be bad. If you plan on keeping your halfmoon in a tank with tetras stick to neon’s, cardinals, embers, and rummy nose tetras.

(Find out more about the types of tetras that can live with bettas.)

Danio Fish

Another shoaling species, Danio fish varieties can also cope well with sharing a tank with Halfmoon bettas. One thing to note is that danios can often require colder water. If you plan on putting them in a tank that’s warm enough for your betta, you may end up simulating breeding season and ending up with more danios than you expected.

Kuhli Loaches

These eel-like scavenger fish are a good tankmate who will pick up any excess food your betta drops. As nocturnal creatures, they often hide together during the day and then become more active at night when your betta is sleeping, minimizing the potential for aggressive interactions.

Cory Catfish

Corydoras or Cory Catfish are schooling fish that prefers to dwell at the bottom of the aquarium, slightly out of the betta fish’s space. There are so many different types of cory catfish you can choose from, and all of them are going to be amazing tank mates for your betta!


Here are some frequently asked questions people have about halfmoon bettas!

How Much Do Halfmoons Cost

The popularity of the Halfmoon betta fish means that it is relatively cheap and easily available in most countries. While aquarium and pet shop sites list male and female Halfmoon bettas for less than $15 and as low as $3.50, you should also factor in the costs of care and upkeep of your fish.  

The initial outlay for a tank and outfitting may be $205 – 345. Annual expenses, including electricity, food, and water conditioner, could be around $80 – 110.

Are Halfmoon Bettas Aggressive?

Yes, halfmoon bettas are just as aggressive as any other type of betta. However, with enough space, and hiding places, you can put them in a tank with other fish!

Can You Put Halfmoon Bettas Together?

You should never put male halfmoon bettas together. If you do want to keep halfmoon bettas together, either opt for females, or use a large enough tank with a tank divider. Even then you should ensure they can’t see each other.

How Big Do Halfmoon Bettas Get?

Long-tailed Halfmoon bettas generally reach a little over 3 inches, with their tail length included. Hybrid species may be longer.

Can Halfmoon Bettas Jump

All bettas can jump, as this is one of the ways they move around rice paddies. However, if the conditions in your tank are good, your halfmoon shouldn’t jump out. You should always keep a lid on the tank to stay safe.

Are Doubletail Halfmoon Bettas Rare?

Double tail bettas have two distinct tails due to a genetic mutation, which means that their caudal fins are separated at the base and grow in two lobes. The double tail Halfmoon betta is rare due to a low survival rate amongst its offspring.


Halfmoon bettas are betta fish that have a tail capable of spreading exactly 180 degrees. They come in all betta fish colors and in both a short-tailed and long-tailed form. With the right conditions and the right care, your Halfmoon betta can enjoy a long, healthy, and happy life for many years to come.