Mollies vs. Guppies: Similarities and Differences

Mollies vs. Guppies: Similarities and Differences

Molly in a tank with guppies

Mollies and guppies are small-sized fish that are in great demand for community aquariums.

But what are the similarities and differences between the two?

Similarities Between Mollies and Guppies

Both mollies and guppies are small, colorful, and relatively easy to handle fish.

They both belong to the Poeciliidae family and hence share many similarities.

Given below are a few of the similarities between mollies and guppies.

Aquarium Set Up

Mollies and guppies thrive in aquariums with lots of vegetation and hiding spots.

They enjoy swimming in open spaces. However, both need hiding spots to take shelter if they feel threatened or stressed.

Both mollies and guppies prefer warm water temperatures between 72°F to 80°F (22.2°C to 26.6°C).


Mollies and guppies are livebearers, meaning they give birth to live fry rather than laying eggs.

The females will keep the fry inside them until birth.

However, both fish species are also known to eat their fry.

So you need to be vigilant and separate the fry from their parents so that they don’t get eaten.

Dietary Requirements

Mollies and guppies are both omnivorous and eat flakes, pellets, frozen foods, live foods, and vegetables.

Maintaining a balanced diet with adequate protein is essential for both of them to stay healthy and active.

However, both fish species are always ready to eat.

So it’s essential to avoid overfeeding since it will impact them and the water quality.

Social Nature

Mollies and guppies prefer living in groups since they are social fish that enjoy swimming together.

Mollies and guppies are both docile fish that can be kept with other peaceful species of similar size.

These fish can get along with others of the same size with compatible personalities.

Easy to Manage

Mollies and guppies are an ideal choice for novice aquarists.

They are hardy fish that can survive in a variety of water conditions.

Both of these fish species can adapt quickly to various aquarium conditions.

Ideal for Community Aquariums

Mollies and guppies are often suggested for community aquariums.

They get along well with other species of a similar size and temperament.

So they are an excellent choice for aquarists wanting to set up a vibrant aquatic habitat.

They also add color and activity to the tank, making them popular among all aquarists.

Differences Between Mollies and Guppies

Though mollies and guppies share many similarities, there are a few differences between these two fish species.

Given below are a few of the differences between mollies and guppies.


Both mollies and guppies can improve the aesthetics of an aquarium due to their unique appearance.

Mollies boast a wider variety of colors than guppies, ranging from black and white to red and yellow.

On the other hand, guppies generally have a more muted color palette, limited to only a handful of colors.


Molly that is larger than guppies

Guppies typically have a more slender body shape than mollies and are also smaller.

Mollies can grow up to four inches in length, making them larger than guppies.

Guppies can grow only up to 1.5 inches in length. However, there are a few instances where guppies have grown larger.


Mollies and guppies are known for their adventurous behavior, often exploring every nook and corner of the aquarium.

Guppies are much more docile than mollies and rarely act aggressively toward other fish.

However, mollies can display aggression toward guppies if they are cramped for space in smaller tanks.


Both mollies and guppie prefer dense vegetation. It gives them a sense of security.

Guppies are freshwater fish native to the rivers and tributaries of South America.

In contrast, mollies are hardy fish that can survive in brackish and freshwater environments.

Tank Maintenance

Mollies and guppies need regular water changes to stay healthy.

Mollies require more meticulous tank maintenance than guppies because they are more sensitive to water quality.

In contrast, guppies are more tolerant than mollies. However, they also need regular water changes to stay healthy.

How to Keep Mollies and Guppies Together in The Same Tank?

Yes, mollies and guppies can live together. However, you must create an environment that allows both species to flourish.

Given below are a few tips to keep mollies and guppies together.

Buy a large tank.

It’s essential to set up a large tank because both mollies and guppies breed a lot.

A large tank can also help create plenty of hiding places for the fry if you want to keep them in the same tank.

Keep a lot of plants.

Plants help the aquarium as they oxygenate the water and remove waste.

They also provide smaller fish a place to hide when they are threatened or chased.

Feed them well.

Both mollies and guppies have a large appetite.

However, overfeeding can adversely impact their health and tank water quality.

Feed them a balanced diet that includes plants and meat at least once or twice daily. This will ensure that every fish gets to eat.

Maintain water temperature.

Guppies and mollies need warm water to thrive. So it’s essential to use a water heater in their tank.

It will keep the water temperature stable and prevent any stress from sudden temperature changes.

Control the population.

If you don’t want your tank population to explode, it’s important to only keep fish of the same gender together.

Additionally, remove the pregnant females before birth to keep the population under control.


Guppies and mollies have similar dietary requirements, are social, need a similar aquarium setup, and are ideal for community tanks.

However, they differ in appearance, size, behavior, and habitat.

Despite these differences, you can keep them together in the same tank by maintaining the water parameters and providing adequate swimming space.

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