The Complete Guide to Caring for Round Tail Betta Fish

icon author linh nguyen

By Linh Nguyen Updated on 01 Mar 2023

For many years, the round-tailed betta has been the most frequent winner at the IBC show. Before the Halfmoon form appeared, the round tail was the most symmetrical single tail in existence and was highly favored by the judges. This variety is like a Plakat but with a larger tail; almost like a Halfmoon but never having a tail that opens into a "D" shape.

After the Halfmoon tail form appeared, they gradually lost their position and could not compete with modern fish lines. Today, one will very rarely see a Roundtail fish. However, they still have a unique beauty that no other betta has.

In this comprehensive guide, we’ll breakdown everything you need to know about Roundtail Bettas including their origin story, care requirements, and fun facts so that you can make an informed decision before deciding if they’re right for your aquatic needs. With some basic know-how, you’ll be well on your way toward enjoying these beauties in no time!

A red round tail betta fish

A red round tail betta fish

1. What is round tail betta fish?

The Round Tail betta is also known as Fantail betta, this is one of the basic tail forms of betta fish. The term "round tail" is most commonly used to describe a single-tailed betta with rounded caudal edges.

This betta line is a single-tailed betta with a rounded edge and is often confused with a delta tail or even a super delta tail. Even without being misnamed, you won't often find them placed in the class of Round-Tails, but rather in Single-Tails.

For many years,  the round-tailed has been the most frequent winner of the IBC show. Before the Halfmoon form appeared, this was the most symmetrical single-tail and was greatly favored by the referees.

Today, this line is undervalued and cannot compete with modern fish lines such as Plakat, Halfmoon, and most recently Crowntail. Although many of these can look very symmetrical, they would not place well in IBC-sanctioned shows, which favor the 180-degree angle and straight edges of the "HM" variety. Therefore, along with Veiltail and Spadetail, the Roundtail Betta line gradually disappeared and was less developed.

2. Round tail betta fish facts

NameRound tail Betta Fish
Another nameFantail betta
Size2 – 3 inches (about 5 – 7 cm)
Weight3 - 5 grams
Lifespan2 - 3 years, up to 4 years
PersonalityRelatively more aggressive than another line
Tank size2 - 5 gallons
HabitatMany aquatic plants
Temperature75 - 86 °F (24-30 °C)
PH level6.5 - 7.5
Nitrite levels0 ppm
Food & dietEat 1 to 2 times a day

2.1. Identification

The round-tailed betta fish is characterized by a single-tailed form, which is wider than the Plakat but smaller than the Halfmoon. The tail edge is not straight but rather rounded like a propeller. Tail rays usually only branch at level two. Additionally, they also only have primary colors such as red, black, and Cambodian.

2.2. Size

The average size of a male round tail betta is two to three inches in length, while females are typically smaller at one and a half to two inches. Males can grow up to four inches long, however, this is unusual and not the norm. In the picture below is a male fish 5 weeks old and it has reached a size of 1.65 inches - equivalent to 4.1 cm. And like other betta species, their size will depend heavily on water quality, habitat, and nutrition.

A 5-week-old male round-tailed betta fish reaches a length of 4 cm.

A 5-week-old male round-tailed betta fish reaches a length of 4 cm.

2.3. Lifespan

The life span of round-tailed bettas is usually shorter than most other types of bettas. This is likely due to their unique tail shape, which makes them more susceptible to disease and parasite infestation. The average life span of a round-tailed betta is two to three years, while some can live up to five years in ideal conditions. 

In comparison, the common Siamese fighting fish (Betta splendens) ranges from two to four years in captivity but can live up to five or even ten years with proper care. 

The life span of round-tailed bettas can be extended by providing them with a high-quality diet, clean water, and a properly maintained tank. They should also be provided with plenty of hiding spots, as this will reduce stress and help them stay healthy for longer periods of time. With proper care, it is possible for round-tailed bettas to live up to their maximum lifespan of five or more years.

2.4. The Behavior

Round-tail bettas are unique species of betta that exhibit distinct behaviors compared to other species. They tend to be more active and social when kept in an aquarium with one or two compatriot round-tailed bettas, and can often be seen chasing each other around the tank. They are also typically more friendly towards other fish than their counterparts; they have been known to peacefully coexist with neon tetras, guppies, mollies, and others.

When threatened or agitated, round tails will flare up their fins just like any other betta would; however, they are usually less aggressive overall. If a fight is necessary though, they won’t back down without putting up a good fight.

2.5. Male

A male round tail betta fish has an eye-catching appearance. Its body is usually a deep, iridescent red, blue, or green color with red accents along the fins and tail. The tails can sometimes have stripes or spots that add a unique flair to their look. The fins are long and flowing, creating a majestic look that is sure to turn heads.

Male betta fish also tend to show off their coloration better when they flare out due to their long, flowing fins.  The most noticeable feature of this type of betta fish is its tail, which ranges in full-circle shapes. This species also features two barbels (whisker-like appendages) around its mouth that help it sense food in the water. Overall, the male round tail betta fish is an attractive specimen that stands out even among other betta fish varieties.

2.6. Femal

Female round tail bettas are known for their shorter and lighter fins compared to their male counterparts. They also have a smaller body size and their shape is slightly bulbous forward. The overall appearance of these fish is typically not as prominent as male bettas, looking more like wild Splendens. 

In terms of behavior, they are peaceful and can do well in small community tanks with other non-aggressive fish. While they may not be as active as male bettas, they enjoy exploring their tank and swimming around rocks or plants.

A female round-tailed betta fish is smaller in size and less colorful than a male.

A female round-tailed betta fish is smaller in size and less colorful than a male.

3. Round tail Betta Care

In terms of care, round-tailed bettas don’t require any special attention; they do well in warm waters and can usually be left to their own devices with little interference from the keeper. They enjoy a variety of foods, including pellets, flakes, and live or frozen food. As with any other fish species, it’s important to provide adequate filtration and clean water. With proper care, round-tailed bettas can live up to five years in captivity.

3.1. Tank size

When it comes to tank size for keeping a round-tail betta fish, the minimum requirement is at least 2 to 5 gallons of water. This is important as these types of bettas need this amount of space in order to grow properly and thrive in their environment. 

Alternatively, you can also select between a square or a round tank for your betta fish. The former should be a minimum size of 10 x 10 x 15 cm while the latter needs to have a diameter of 15 cm. Aquariums for bettas do not necessarily need to have a filtration and aeration system, but you must ensure that the water is clean and should be changed every 2 to 3 days. Additionally, you can also equip more heaters or LED lights.

In general, bigger tanks are better than smaller ones since they provide your round tail bettas with more room to explore, swim, and play. It is also great for keeping their water clean and healthy so that they can be happy and live long lives. So if you have the means, a larger tank is definitely recommended!

3.2. Food & diet

Round tail betta fish require a varied diet to stay healthy and happy. The best way to do this is to feed them 1-2 times a day with only the right amount of food each time. Feeding should be done in the morning or early afternoon, as any food left over after 5 pm should be taken out in order not to pollute the aquarium water. It's important to provide your betta with a nutritious diet that contains plenty of protein for their needs. Betta fish flakes, pellets, or frozen foods such as bloodworms, shrimp, and daphnia are all good sources of protein that can provide essential nutrients for your betta’s health. Additionally, occasional treats like freeze-dried brine shrimp, tubifex worms, and more can be included to supplement their diet. Vegetable matter can also be offered in small amounts as a treat or supplement.

Let's remember that overfeeding your betta is just as dangerous as underfeeding them, so always make sure you're feeding them the right amount for their size and health needs.

3.3. Water parameters

In order to provide a healthy and thriving environment for round tail bettas, it is important to pay close attention to the water parameters in their tank. The ideal temperature range for keeping round tail bettas is between 75-86 °F (24-30 °C). Additionally, the pH level should be maintained between 6.5-7.5 and the hardness should be between 5-19 dH. Ammonia and nitrite levels must also remain at 0 ppm while nitrate levels should not exceed 20 ppm. To ensure that these parameters are stable, regular water changes of 25% every two weeks are recommended.

Driftwood, plants, rocks, and caves are all great options. Round tail bettas can also be kept in community tanks provided that the tankmates are peaceful and do not outcompete them for food.

Video of 5-week-old round tail betta fish

3.4. Tank Mates

When picking tankmates for a round tail betta, there are many suitable options to choose from. Many species of peaceful fish, such as small tetras and danios, can be kept with the bettas in the same aquarium. Additionally, some snails or dwarf shrimp can also make good tankmates as long as they are not aggressive toward the betta. Let's remember that when choosing tankmates for your betta it is best to select smaller fish or invertebrates so they do not outcompete the betta for food or space; if necessary, provide additional feeding spots and hiding places in order to ensure all inhabitants are receiving adequate nutrition and shelter.

In terms of plants, many low-maintenance species are suitable for round tail bettas. Vallisneria, Anubias, and Java Fern are all hardy options that can tolerate low to moderate lighting and require minimal pruning or maintenance. Floating plants like duckweed or frogbit can also be added to create hiding places for the fish, as well as shade from direct light. Live plants provide a natural environment and benefit the aquarium by increasing oxygen levels and providing beneficial bacteria that help break down fish waste.

3.5. Common possible diseases

Raising round tail bettas can be a rewarding experience, but it is important to be aware of some of the common health problems that these fish may face.

  • Bacterial infections are one of the most frequently seen diseases in round tail bettas, and signs such as clamped fins, labored breathing, patches on the body, or ulcers can indicate an issue.
  • Dropsy is another condition that causes swelling due to fluid buildup.
  • Fungal infections are also possible, with symptoms including fuzzy white growths on the fish’s body or slime coat loss. 
  • Lastly, parasites should not be overlooked when caring for these fish; ich (white spots), velvet (golden-brown dust) or anchor worms (visible wriggling worms) are all potential problems.

It should also be noted that bettas line can suffer from stress-related illnesses as well. Stress in fish is often caused by poor water quality or overcrowding, an incorrect pH level, or temperature fluctuations. Signs of stress include dull coloration, listlessness, and hiding or refusing food. If left untreated these issues can become more serious or even fatal.

Remember that prevention is always better than cure, so taking the time to ensure the health of your fish will pay off in the long run. Regular water testing and monitoring of temperature and pH are essential to maintaining a suitable habitat for your bettas. A regular schedule of tank maintenance should also be followed, including cleaning filter media, gravel vacuuming, and replacing used water with fresh pre-conditioned water. All these steps can help reduce the risk of common diseases when raising your bettas.

An adult red round tail betta fish

An adult red round tail betta fish

4. Breeding

Breeding round tail bettas is a relatively straightforward process compared to other varieties of betta fish. The breeding process can begin when the fish are approximately three months old. During spawning, the female will lay around 200 eggs which will then need to be separated into an incubation tank or hatchery box with plenty of oxygen. After hatching, the remaining fry must be carefully monitored in order to ensure their survival and maturation rate. It is typical that only about 50 out of the original 200 eggs will survive this selection process and make it through to maturity. When the juvenile fish school together, there tends to be a higher proportion of male fish in comparison to females so breeders should take this into consideration when pairing their fish for breeding. 

As the fish mature, they will develop their distinctive round tails which are so characteristic of this variety of betta fish. If you're interested in attempting to breed these beautiful aquatic creatures, ensure that your fish have the appropriate environment and diet to promote good health before starting the process. With patience and dedication, you'll soon be able to produce some stunning specimens of round tail betta fish!

Please refer to our betta breeding tutorial series for more detailed instructions.


In summary, owning a Roundtail Betta is a rewarding experience. The combination of their stunning colors and remarkable ability to adapt to nearly any aquarium environment make them one of the most desirable and beloved fish in the hobby. As long as you’re mindful of their basic care requirements — such as clean water conditions and ample swimming space — they will thrive in your home. Don’t forget to take regular measurements of the pH balance and temperature to ensure your tank never dips below or rises above recommended levels. Finally, be sure to incorporate plenty of interesting objects into their habitat—either natural or artificial works just fine! Tankscape bettas love exploring new things, so by giving them a few fun additions they can explore you'll be giving them endless hours of entertainment. All in all, Roundtail Bettas are a great choice for experienced hobbyists and first-timers alike! If you'd like more tips on keeping happy bettas, let me know in the comment below - I'm always ready to give advice.

Leave a comment

Your email address will not be published. Required fields are marked (*)

Please fill out this field.
Please fill out this field.
Please fill out this field.