Molly Fish Compatibility: Which Fish Can Live with Mollies?

Molly Fish Compatibility: Which Fish Can Live with Mollies?

Are you considering adding mollies to your aquarium but unsure about the best tank mates for them? Understanding the compatibility of mollies with other fish species is crucial for maintaining a harmonious and thriving aquatic environment. In this article, we will explore the various factors that influence molly fish compatibility, including water conditions, temperament, and size. By the end, you’ll have a clear understanding of which fish can peacefully coexist with mollies, allowing you to create a vibrant and well-balanced community tank.

Factors to Consider for Molly Fish Compatibility

Tank Size

The size of the tank is an important factor to consider when determining the compatibility of mollies with other fish. Mollies are active swimmers and they require ample space to swim freely. It is recommended to provide at least 20 gallons of tank space for a small group of mollies. This not only ensures their physical well-being but also helps reduce aggression among tank mates.

Water Parameters

Mollies are known to prefer slightly brackish water conditions, which means they thrive in water that has a small amount of salt content. However, they can also adapt to freshwater environments. When considering tank mates for mollies, it is essential to ensure that the water parameters are suitable for all the fish. The pH level should be maintained between 7.5 and 8.5, and the water temperature should be kept around 72-78°F (22-26°C). By maintaining the appropriate water conditions, you can ensure the compatibility and overall health of your mollies and their tank mates.


Mollies, especially males, can exhibit aggressive behavior towards other fish, especially those with long fins or vibrant colors. Therefore, it is important to select tank mates that can withstand or avoid such aggression. Peaceful and moderately sized fish like platies, swordtails, and certain tetras can make good companions for mollies. Avoid keeping mollies with fin-nipping or aggressive fish, as it may lead to stress and harm to both the mollies and their tank mates.

Feeding Habits

Understanding the feeding habits of mollies is essential in ensuring their compatibility with other fish. Mollies are omnivorous and require a varied diet consisting of both plant matter and protein-rich foods. When selecting tank mates, it is important to choose fish that have similar dietary requirements. This ensures that all the fish in the tank receive adequate nutrition and reduces the chances of aggressive behavior due to competition for food. Additionally, providing a balanced and nutritious diet for your mollies and their tank mates promotes overall health and well-being.

By considering factors such as tank size, water parameters, aggression, and feeding habits, you can make informed decisions when selecting compatible tank mates for your mollies. Creating a harmonious and thriving community tank will not only enhance the well-being of your mollies but also provide an aesthetically pleasing and enjoyable aquarium experience.

Compatible Fish for Mollies


Guppies (Poecilia reticulata) are one of the most popular and compatible fish to keep with mollies. These small, colorful fish are known for their peaceful nature and vibrant displays. Guppies are similar to mollies in terms of their preferred water conditions and temperature requirements. They thrive in freshwater aquariums with a temperature range of 72-82°F (22-28°C) and a pH level between 6.8 and 7.8.

Mollies and guppies also share a similar diet, making it easy to cater to their nutritional needs. Both species are omnivorous, meaning they eat a combination of plants and small invertebrates. Providing a varied diet that includes high-quality flakes, pellets, and occasional live or frozen foods will keep both mollies and guppies healthy and satisfied.

When it comes to compatibility, mollies and guppies get along well due to their peaceful nature. They are both community fish and enjoy swimming together in the same tank. However, it’s important to maintain a proper male-to-female ratio to prevent any aggression or stress among these species. A good rule of thumb is to have two to three female guppies for every male to balance the dynamics and reduce the chances of harassment.


Platies (Xiphophorus maculatus) are another excellent choice for tankmates with mollies. These small, lively fish are known for their bright colors and playful behavior. Just like mollies and guppies, platies prefer similar water conditions and temperature ranges. Keeping the aquarium temperature between 72-82°F (22-28°C) and maintaining a pH level of 6.8 to 7.8 will ensure the optimal environment for all three species.

Platies, like mollies, are omnivorous and will happily consume a varied diet. Providing them with a balanced mix of flakes, pellets, and occasional live or frozen foods will keep them healthy and vibrant. It’s worth noting that platies are known to be prolific breeders, so if you don’t want to end up with an overpopulated tank, consider having a mix of male and female platies or adding more female platies to maintain a healthier male-to-female ratio.

In terms of compatibility, mollies and platies generally get along well. They share a peaceful temperament and enjoy swimming together in community tanks. However, occasional territorial behavior might be observed, especially during breeding periods. Providing ample hiding spots and vegetation will help alleviate any conflicts and create a harmonious environment for both species.


Swordtails (Xiphophorus hellerii) are another suitable choice for tankmates with mollies. These elegant fish are known for their elongated tails resembling a sword, which adds a unique touch to any aquarium. Similar to mollies, guppies, and platies, swordtails prefer similar water conditions. Maintaining a temperature range of 72-82°F (22-28°C) and a pH level between 6.8 and 7.8 will ensure the well-being of all these species.

Swordtails, like their counterparts, have an omnivorous diet. They thrive on a combination of high-quality flakes, pellets, and occasional live or frozen foods. A varied diet will keep swordtails healthy and enhance their vibrant coloration.

When it comes to compatibility, mollies and swordtails generally get along well. Both species are peaceful and enjoy swimming together. However, it’s crucial to maintain a balanced male-to-female ratio and provide enough space for each fish to reduce any potential aggression. Adding plants and decorations to the aquarium will offer hiding spots and territories for each species, promoting a harmonious coexistence.

Remember to monitor the behavior and well-being of all fish in the tank and make adjustments if necessary. With proper care and attention, a community tank consisting of mollies, guppies, platies, and swordtails can create a visually stunning and captivating aquatic display.

Incompatible Fish for Mollies


Bettas, also known as Siamese fighting fish, are not suitable tank mates for mollies. These beautiful and vibrant fish are known for their aggressive nature, especially towards other males. Mollies, on the other hand, are peaceful and easy-going fish. When kept together, bettas may attack and nip at the fins of mollies, causing stress, injury, and even death. It is best to keep bettas in their own separate tanks to ensure their well-being and prevent any harm to your mollies.


While angelfish are graceful and captivating creatures, they are not compatible with mollies. Angelfish are known to be territorial and can become aggressive towards other fish, especially smaller ones like mollies. Mollies may be seen as potential prey by angelfish, leading to chasing, aggression, and even injury. Moreover, angelfish prefer warmer water temperatures compared to mollies, which can create an unsuitable environment for both species. It is advisable to keep mollies and angelfish in separate tanks to avoid any conflicts and maintain a harmonious aquatic environment.


Cichlids, known for their vibrant colors and fascinating behaviors, are not compatible tank mates for mollies. These aggressive and territorial fish can pose a threat to the peaceful nature of mollies. Cichlids have a tendency to dominate the tank, which can lead to stress and harm for mollies. Moreover, cichlids have specific water parameter requirements, such as pH and hardness, which may differ from those preferred by mollies. Keeping them together can result in an incompatible environment and lead to health issues for both species. It is recommended to keep mollies and cichlids in separate setups to ensure the well-being of both fish.

When considering tank mates for mollies, it is crucial to choose fish that have similar temperaments, water parameter preferences, and size compatibility. By avoiding bettas, angelfish, and cichlids as tank mates, you can create a peaceful and thriving aquarium environment for your mollies.

In conclusion, when considering the compatibility of mollies with other fish, it is important to take into account their peaceful nature and specific water requirements. While mollies can generally coexist with a variety of fish species, it is crucial to ensure that the tank conditions are suitable for all inhabitants. Optimal water parameters, adequate space, and compatible temperaments are key factors to consider when selecting tank mates for mollies. By carefully researching and selecting appropriate companions, aquarium enthusiasts can create a harmonious and thriving aquatic community.