Everything about Balloon Molly Fish: Tank size, Diet, Breeding, and more

Balloon Molly fish is a unique freshwater fish that are bred extremely short and round. The name; balloon Molly truly justifies the appearance of this fish as their bellies are round and swollen with arched backs and extended dorsal fins.

One other fact about Balloon Molly fish is they are truly man-made and a result of selective breeding to have scoliosis. Therefore, they have a short lifespan with a life full of colors and patterns

In this article, we’ll explore other areas of Balloon Molly fish and how it enhances the beauty of your aquariums.

Key Takeaways

  • The balloon belly Molly fish is a result of selective breeding, which was specifically bred to have scoliosis. 
  • These fish have a deformity that causes arched back and swollen, protruding belly
  • They are smaller in size and make great community tank fish but should never be kept with large aggressive fish 
  • They have a relatively shorter lifespan than other molly fish species

Fish Species Overview

Scientific NamePoecilia sphenops
Common NameBalloon Molly, Balloon Belly Molly, Belly Mollies, Pot Belly Molly
FamilyPoecilia Latipinna
OriginNorth and Central America
Care LevelEasy
Lifespan3 to 5 years
Tank LevelAll levels
Minimum Tank Size10 gallons for a single fish
Temperature Range75°F to 82°F
Water Hardness10-25 dGH
pH Range7.5 to 8.5
Filtration/Water FlowSlow moving
Water TypeFreshwater, tropical fish
Difficulty to BreedEasy
CompatibilityCompatible with peaceful community fish
OK, for Planted Tanks?Yes

What Are They?

Balloon Mollies (Poecilia latipinna) are livebearers. Live-bearing fish species are those in which female balloon mollies give birth to live baby balloon mollies. These fish species are native to Central America and Mexico. Like many other live-bearing fish species, Belly mollies grow very quickly and reach maturity at the age of 3 months. This molly is a hybrid breed of the original molly fish.

Origin And Habitat

The Balloon Molly fish originates from North and Central America. Like Guppies, Platies, and Swordtails, these fish species also belong to the family Poeciliidae. Many aquarists believe the origin of Balloon Molly is the Gulf of Mexico, especially from the brackish water of Texas, Louisiana, and Mexico.

Chances are, they are found in the freshwater streams and rivers in those regions. Today, Balloon Molly is a popular aquarium fish that is widely kept and enjoyed in the fishkeeping world because they are vibrant, beautiful, hardy fish and easy to care for.


The Balloon belly Molly fish are small fish with a beautiful, colorful appearance and a unique body shape. Their body shape stays true to their name because these fish species are balloon shaped. They have round bellies and small heads. Their bodies are covered in shiny scales that showcase a subtle metallic but graceful luster.

Balloon Molly in Fish Tank

The Balloon belly mollies are most commonly found in black and orange colors. However, the color variety in these ballon mollies is diverse. They can be found in hues of silver, gold, and green. The dorsal fin of Pot belly mollies is large, running through the top of their body. They also have a small present near their tail.

The difference between male balloon mollies and Balloon Molly females is in their bodies. The male fish are smaller and slimmer than female mollies. Male fish also have modified anal fins that fertilize the females during breeding. Comparatively, female mollies are bigger in size and have round anal fins.

Common Varieties (Types)

The most common types of Balloon Molly are black and orange. However, the beauty of these aquarium fish is not limited to these colors. There are several varieties of Balloon Molly that can enhance the beauty of your home aquariums.


They are majorly black in color, with rounded bodies and small heads. Their distinctive appearance gives them the shape of a balloon. They also have a shiny metallic sheen on their bodies that makes them stand out in your aquariums.


As the name suggests, the Dalmatian ballon mollies have pearl-white or cream-colored bodies with black spots all over, giving them a Dalmatian-like appearance.

Gold Pot Belly

The bodies of hold pot belly Molly are yellowish-golden with a metallic shine. The Gold variety is very popular due to its bright, lustrous color and easy-for-care nature.

Silver Belly

Silver belly balloon mollies are silver in color with a metallic shine. When they swim, they reflect light that looks beautiful and adds a unique touch to your aquariums.

Lyretail Fish

Unlike other fish, the Lyretail Balloon mollies have a lyre-shaped caudal fin that is longer and flowier than other fish species.


The marbled and multicolored variants of fish species have a beautiful multicolored body with patterns of black, white, and orange colors that resemble the marbles. Hence, the name. The intensity of the colors of Marble largely depends on other factors such as diet, water temperature, water parameters, and more.


Unfortunately, the lifespan of Balloon Mollies is short compared to other fish species. The average lifespan is around three to five years. One major reason that contributes to the short life expectancy is selective breeding. Also, their large bellies make it difficult for them to swim, so they are slow swimmers and slow feeders.

The lifespan of Balloon Molly depends on water conditions; they thrive in the freshwater tank because brackish or saltwater makes them susceptible to fish diseases.

Average Size

Balloon mollies are small fish, growing around 3 to 4 inches in length. Also, the size of ballon mollies depends on their diet, water temperatures, genetics, and Tank setup.

In general, female balloon mollies are larger than males and has round bellies with more prominent anal fins.

Balloon Molly Fish Care

Fortunately, as pretty as they seem, balloon Molly is peaceful fish that is easy to keep in a freshwater tank. They are also great for beginners in the aquarium hobby.

However, you should always care for their aquarium conditions and maintain their ideal water parameters to keep them happy and thriving.

Tank Setup

As mentioned earlier, balloon mollies are not challenging species. They need their ideal water conditions and a properly balanced diet to thrive in your fish tank. Also, some basic aquarium equipment, such as filters and aquarium heaters, are essential.

Tank Size

Though Balloon Mollies are small fish species, they need ample space for swimming as they are active fish. Thus, a fish tank of 10 gallons is the bare minimum for Ballon Mollies. If you’re keeping more than one fish, then consider adding 2 to 3 gallons of aquarium water per fish to keep them entertained and happy.

Remember, providing enough swimming space and a balanced diet will help your Balloon Mollies grow to their best potential. If possible, go over 10 gallons to maintain stable water conditions and provide more free swimming space to your finned pals.

Water Parameters

The tank water of Balloon Mollie’s tank should be slightly alkaline with a pH of around 7.5 to 8.5. The ideal water temperatures are 75°F to 82°F. Balloon Molly fish prefers water hardness of around 10-25 dGH.

I also advise performing regular water changes with 10% to 20% of the tank volume to keep your tank water healthy and free of bacteria.


For the lighting, keep it lightly dim as Balloon Molly fish do not appreciate high-intensity lighting. They are naturally brackish fish and prefer a lower-light environment. Also, consider a lighting schedule of no more than 12 hours followed by 12 hours of darkness.

Choose aquarium lights that are appropriate for your Balloon Molly and live plants. I recommend installing adjustable LED lights to avoid algae growth.

Aquatic Plants

Balloon Molly fish appreciates a heavily planted aquarium with lots of hiding spots. Therefore, it’s crucial to add live plants to your fish tank. The best aquatic live plants for balloon mollies are low light plants such as:

  1. Java fern
  2. Anubias
  3. Amazon Sword
  4. Java moss
  5. Water sprite

Tank Decorations

Balloon Mollies love hiding places and swimming space. Therefore, a well-decorated tank is crucial for their health. You can use rocks and driftwood to create hiding places and a natural-looking environment. Also, caves and tunnels are made of aquarium-safe materials and are an excellent option for creating fun hiding places. Besides, you can add other items, such as a few decorative rocks, ceramic statues, and fake corals, to add visual aesthetics.

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Balloon mollies enjoy sandy substrates as they are easy to clean and never hold debris. You can also use gravel instead of sand or a combination of both. In any case, be mindful of the depth of the substrate, especially for a planted tank. The depth of your substrate should be no less than 2 to 3 inches.

Tank Maintenance

Proper tank maintenance is the key to keeping your fish’s health in optimal condition. Thus, regular water changes should be done to maintain the water quality. Also, water changes of 20% to 30% are recommended in a week to get rid of toxins and fish waste.

If you’ve installed a filter, make sure to clean it regularly and replace filter media. I also advise installing an aquarium thermometer to monitor the water temperature and pH to prevent stress and illness in your fish.

Lastly, do regular water testing to rule out any problems with the water quality and keep your tank a safe place for your balloon Mollies.

Community Tank Mates

Balloon belly mollies are small, peaceful fish that can live with other species with the same temperament peacefully. However, avoid keeping them with larger, active, and aggressive fish, as balloon mollies are slow swimmers and slow eaters. The larger, more aggressive fish might bully and harm your little belly mollies.

Platy Fish

Here are the following community tank mates that are ideal for keeping with your balloon mollies.

  1. Guppies
  2. Platies
  3. Swordtails
  4. Tetras (Neon tetras, cardinal tetras)
  5. Corydoras


If you want to breed balloon mollies, I’ve some great news for you.

Breeding balloon mollies in an aquarium is not a challenging task, provided that you’ve given them the right meaty foods, proper aquarium size, and ideal water quality conditions.

Balloon Mollies are also very peaceful fish, ideal for community tanks. However, they eat their young ones. Therefore, it’s best to separate Molly’s babies from their parents. The best part is the female Molly is able to reproduce 40 to 50 tiny babies. Thus, breeding becomes a breeze. Also, your breeding tank should have live plants to maintain the’s health and provide your fish with lots of hiding places.

Here are some of the steps you can take to breed Balloon Mollies (video source):

  1. It’s advisable to prepare a separate breeding tank where the aquarium size should be at least 30 gallons. Also, set up an aquarium heater, filter, and good lighting to encourage healthy breeding.
  2. Pick your best male and female pair and introduce them gradually into the breeding tank. While choosing the breeding pair, make sure the male is smaller in size than the female Molly.
  3. Provide them with protein-rich food, including live or frozen food such as frozen brine shrimp, to ensure proper health.
  4. Once the breeding pair is ready, mating will take place naturally. Balloon mollies are livebearers. After the female is fertilized, she will carry the fry until they are ready to be born.
  5. When the female Molly is pregnant, it is advisable to separate the males and females to avoid aggression towards the Molly fry.
  6. After 60 days or so, the female Molly gives birth to Molly fry. The initial fry diet is crushed flake food, baby Brine shrimp, and commercial fry food. The frequency of meals should be 2-3 times a day.
  7. Once the fry grows, they are moved back to the main tank.

Food And Diet

Balloon belly Molly are omnivores that prefer a simple but protein-rich diet. In captivity, you can feed them a balanced diet including flakes and pellets, live foods, or frozen foods such as bloodworms, shrimps, daphnia, and mosquito larvae; you can also feed them vegetables such as spinach, zucchini, or spirulina flakes.

I also advise feeding algae wafers or pellets in their diet to mimic their natural behavior. And fulfill their instincts.

Common Health Problems

Though Balloon mollies are hardy fish and easy to care for, even for beginner fish keepers, there are times when this fish can be highly susceptible to diseases and illness. The common health problems of balloon mollies are:


Ich is categorized by small white spots on the fish’s skin and fins due to a parasitic infection. Ich can be highly fatal if left untreated.

Fin Rot

Fin rot is a bacterial infection in which the affected fish has frayed, ragged fins. 

Swim Bladder Disease

Poor water quality, bacterial infections, poor hygiene, or overfeeding cause swim bladder disease. The affected fish show erratic swimming behaviors and float to the tank’s surface or may sink to the bottom of the tank.


Dropsy results from a bacterial infection that collects fluid in the fish’s body. The diseased fish seems bloated and well-fed. Dropsy is a fatal disease that might lead to a slow death if not treated properly.

Velvet Disease

Velvet disease is caused by a parasite that causes lethargy, loss of weight, loss of appetite, and difficulty in swimming or breathing. 


How Many Should Be Kept Together?

The Balloon Molly is a peaceful community tank fish that enjoys a group of at least 3 to 5 fish species.

Are They Hard To Keep?

No, Balloon Mollies are easy to keep and highly adaptable fish. But there are certain requirements to keep them happy and thriving, including their ideal tank size, water temperature, water parameters, live plants, and more.

Do They Need A Heater?

Yes, Belly mollies need a heater since they are tropical fish that need a stable water temperature of around 72-82°F.

How Many Should Be Kept Together?

As many balloon mollies as you want since they are social and peaceful fish species. However, consider the tank size and avoid overcrowding the tank. 

What Temperature Do They Like?

Balloon belly Molly is a tropical freshwater fish that prefers temperatures around 72-82°F. 

What Size Tank Do They Need?

Balloon belly Molly are small fish, but they need ample swimming space and lots of hiding places. Therefore, a tank of around 10 gallons or more is required to keep them happy.

Do They Breed Easily?

Yes, balloon mollies are easy to breed in captivity. However, you should provide them with a separate breeding tank catering to all their needs to ensure successful and healthy breeding.

Final Thoughts

Balloon belly Molly is a fancy version of the regular mollies. However, they are smaller in size, with a shorter lifespan, and have rounder bellies with arched backs and extended dorsal fins. By the looks and overview of this fish, you may misunderstand it as one of those “high-maintenance fish.” However, they are easy to care for, peaceful, and super hardy fish, selectively bred to adorn your home aquariums.

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