Compatible Tank Mates For Molly Fish

Molly fish, known for their vibrant colors and lively personalities, are a popular choice among aquarists. Keeping Molly fish in a community tank can be a rewarding experience, but choosing suitable tank mates is essential for their well-being and harmonious coexistence.

So which fish makes the perfect mates for mollies? While originally found in the wild and bred for domestication, Molly fish have developed a distinct temperament that sets them apart from other species within the same genus, such as sphenops. Some common tank mates that coexist harmoniously with molly fish are guppies, tetras, platies, and more.  

Molly Fish Compatible Tank Mate (Video)

Now let us check some good tips for choosing the perfect tank mates for your molly fish in order to keep them safe and healthy.

General Overview

Before diving into compatible tank mates, it’s crucial to understand Molly fish. These tropical freshwater fish belong to the Poecilia genus and are native to the warm waters of the Americas. Molly fish come in various colors and fin variations, making them an attractive addition to any aquarium. They are known for their active nature and adaptability, thriving in a wide range of water conditions.

Mollies are less demanding, easy to breed, and only consume a smaller tank capacity of approximately 10 gallons or more. For beginner fish keepers, the black molly is highly recommended as they are hardy fish and are easy to keep.

Their characteristic of getting used to different and evolving water conditions has taken the test of their strength through time and has made them fully adaptive from brackish, freshwater, to even salt-water conditions.

Molly fish diet is described as omnivorous, meaning it is easier to maintain as it can feed on any food available.

Mollies are actively moving sphenops types, so to successfully keep a group, you will need a 13-gallon capacity tank (50 liters) to avoid crowding and comfortably grow your mollies with a stable biotic balance in their habitat.

All About Molly Fish and Their Perfect Tank Mates

Compatible Tank Mates for Mollies

Mollyfish can live with the following in the same tank:

  • Platy
  • Siamese Fighting Fish
  • Neon Tetra
  • Goldfish
  • Angelfish
  • Southern Platyfish
  • Oscar
  • Suckermouth Catfish
  • Green Swordtail
  • Gourami
  • Cichlid
  • Danios
  • Guppies

Molly Fish Behavior

Mollies are most compatible with each other inside a tank with just a small number of males and several females.

They can usually be compatible as co-inhabitants with other sphenops such as Platies, Corydoras Catfish, Swordtails, Angelfish, Plecostomus, Bigger Tetras (Black Skirts, Red Serpaes, Silver tips), Guppies, female Bettas, Endlers, Danios, White Cloud Mountain Minnows, Dwarf Gourami, Bristlenose Pleco, Harlequin Rasbora, Cherry Barbs and even Snails or Shrimps.

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All Molly varieties may differ in appearance and size, but the ways of breeding, caring, and compatibility for all of them are always leveled the same. The Molly fish is distinguished easily because of its elongated body that is a bit flattened from the sides, having relatively larger eyes and an upward mouth.

It does not look as flowy and artsy as guppies or other ornamental fish in their early days, but they gain their maximum size and beauty roughly during their second year after birth.

The male fish grows only up to 3 inches long (6-7 centimeters), while the females may grow to as large as 4 inches (about 10 centimeters) at the age of about six months.

Most of them are colorful, but the Black Molly fish does not have any glitter or spots on its body, which makes it distinct and easy to identify among others because of its “coal-black” color.

Molly fish are active yet peaceable, but they need a spacious tank to prevent aggression, either among themselves or towards other tankmates. To maintain harmony, keep them in groups with more females, a common rule for live-bearing fish.

To prevent stress and aggression, having more female mollies in the tank is crucial. This helps avoid excessive male attention and territorial behavior in smaller tanks.

Appropriate Tank Size

Every fish species has a water condition requirement for their survival, even so for the Molly fish. These fish are active. Therefore, their tank should not be crowded at all.

To successfully grow and keep them, 13 gallons (approx. 50 liters) is a perfect size. Mollies adapt to any new condition in their tank parameters perfectly.

Mollies cannot withstand rapid changes in temperature, so there should be a maintained temperature range of 25-27 degrees Celsius, pH/ acidity levels of 7-8, and water hardness of 20-30 dGH.

Some experienced aquarists recommend adding salt to the tank water, especially when molly fish are kept alone or in quarantine due to parasites or illness. Molly fish also thrive in fresh water conditions, so regular water changes, around 25% of the tank’s volume, are advisable to remove ammonia, nitrites, nitrates, and other nitrogenous compounds from the water.

Creating a densely planted tank is ideal because mollies enjoy nibbling on algae from tank plants. Adequate aeration, filtration, and well-lit areas contribute to their overall well-being in the aquarium.

Feeding Your Molly Fish

Mollies are classified as omnivores. They feed on live, frozen, or artificially processed fish food. They need a large amount of vegetable fibers found in algae or vegetables.

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The wild molly fish consumes a lot of algae in its diet, which is duly manifested in its daily behavior of scraping algae accumulated in its tank glass or decors.

Aside from the processed, ready-to-eat fish flakes available in the market, you can give pieces of boiled cucumbers, squash, or lettuce leaves, as the vegetable component is very important in the fish’s diet.

You may also add regular live food for the fish, such as bloodworms, tubifex, or brine shrimps. Ensure a high-quality food set for your pet mollies to avoid them from getting ill or catching infections, as well as keep the tanks clean and conditioned.


Molly fish are livebearers, much like Guppies. Breeding them is quite simple – just keep a few males and more females in your tank, and they’ll reproduce regularly, with females getting pregnant every month. Males use a specialized organ called a gonopodium to fertilize females securely, and pregnancy lasts 35-45 days, with subtle signs appearing in the early weeks.

When pregnant, mollies become less active and may hide, signaling the need to move them to a separate tank with similar conditions. Birth usually occurs in the morning, with larger females giving birth to a varying number of fry, depending on their age and size.

Juvenile mollies initially cling to tank plant leaves before venturing into open water. During this sensitive period, maintain water quality through frequent changes, and provide microworms or specialized high-quality food to help the young mollies grow quickly.

Frequently Asked Questions

What type of Molly fish should newbie fish keepers buy? 

Black Mollies are a great choice; they are low maintenance, easier to feed, and breed.

Will the Molly fish survive in a bowl? 

This might not be possible because mollies are big fish, with more frequent pregnancies and increased activity; so it could be challenging to raise it in a fish bowl.

Are Mollies aggressive? 

Mollies are typically peaceful fish but can show aggression in overcrowded or imbalanced tanks. To keep a harmonious aquarium, provide ample space and hiding spots, and maintain the right male-to-female ratio. Avoid pairing them with aggressive or fin-nipping fish to prevent conflicts and stress.

How long do mollies live? 

Mollies have an average lifespan of about 3 to 5 years in captivity when provided with proper care and a suitable environment. However, their lifespan can vary based on factors like water quality, diet, genetics, and overall tank conditions.

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Nadine Oraby

My name is Nadine; I am a passionate writer and a pet lover. People usually call me by the nickname “Joy” because they think that I am a positive and joyful person who is a child at heart. My love for animals triggered me to create this blog. Articles are written by vets, pet experts, and me. Thanks for visiting. Your friend, Nadine!

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