Can Goldfish And Mollies Live Together?

Last Updated on 2023-07-31

Goldfish are freshwater fish that are from the Cyprinidae family, which includes other fish such as carp and minnows. Mollies are from the Poeciliidae family, which includes such fish as Guppies and Swordtails. These two fish are popular within private household aquariums; however, can Goldfish and Mollies live together?

So Can Goldfish And Mollies Live Together?

Research and experience would heavily suggest that it’s not a good idea to keep these two fish in the same tank for various reasons. This article will explore how best to manage these fish separately to provide the best care you can for your fish!

(There are plenty of other great tank mates for your goldfish however!)

Fish Temperaments

If you are new to fish keeping, you’ll want to do heavy research into your chosen fish’s temperament! Matching your fish’s temperaments is fundamental to any well-maintained tank! Fish temperaments range from peaceful to aggressive but also include their swimming habits and how their environment affects them.

A Goldfish’s Temperament

Surprisingly, Goldfish are very social animals that have a peaceful nature! They will live better with a group, mostly suiting those of their own kind, but other fish with similar temperaments will be fine.

Goldfish love to swim in the range of their tanks. This means that if you think a Goldfish would be a suitable pet for you, then you need to invest in a tank with plenty of room.

There is a recommended water amount per Goldfish, but we need to take how many fish will be in the tank into consideration, too, to maximize space. This is to ensure they are free to roam and keep that peaceful temperament they are known for!

Mollies Temperament

Mollies are also another peaceful breed of fish! However, they are not recommended to be placed with Goldfish, which may not make any sense due to their temperaments being similar.

This is due to the matter that Mollies have a tendency to become aggressive towards Goldfish! Mollies can become aggressive towards other fish if you have an overcrowded community tank, but some have commented that even just the two cohabitating make the Mollies aggressive!

This could be Mollies asserting their dominance or having a lack of females in the tank. Either way, it’s best to keep the Mollies away from Goldfish to protect their well-being.

(If you have mollies, you could also try keeping them with angelfish!)

Habitats And Tank Requirements

Replicating a fish’s natural habitat is imperative for its happiness. A good tank will provide places to hide for timid fish and room to explore for social schools. We also want to replicate natural temperatures the fish would be accustomed to in nature. By doing this, we help to reduce stress and keep oxygen levels steady.

It’s important to do research into what is good for the fish you want rather than what you feel looks good for the tank. This could be the difference between your pets thriving or succumbing to a short life!

Goldfish Habitat

A Goldfish’s natural habitat is anywhere you would come across freshwaters. This ranges from streams to reservoirs to lakes. In these sorts of terrains, you will expect a lot of rocks, plants, and other fish.

Goldfish Tank Requirements


We know Goldfish are very social fish that love to swim the range of their tanks. We suggest, when investing in this particular fish, accommodating each Goldfish with twenty gallons of water each.

However, for your first tank, use forty gallons for the first Goldfish, and then with each new addition, an additional 20 gallons each time. This means for your first tank, you would want to look for one that holds at least 60 gallons; as we know, Goldfish like to be in pairs or more. If you are thinking of adding more ranges of peaceful fish, you will need to check how much water they’ll need to ensure you can accommodate them too.

Overstocking fish tanks is a serious problem, which will cause your fish problems with stress, and may lead certain non-aggressive fish to become aggressive out of frustration.

pH Level and Temperature

The correct pH level and temperature are important within your tank as they can be the difference between life or death for your fish.

pH levels determine how acidic or alkaline your water may be. Different fish will thrive at different levels, depending on what the waters were like in their natural habitats, even if they have been bred in captivity.

For a Goldfish, the pH level of your personal aquarium is most advantageous, between 7.2 and 7.8. Others may suggest, due to the adaptability of the Goldfish, that they may be able to live in levels outside of this scale. That may work for a small range of time; however, we recommend this level to ensure they do not become sick and die.

Maintaining this pH level is imperative, along with the right temperature. Goldfish are freshwater fish and will do best in waters between 20-23 degrees celsius. Any lower or higher than these temperatures may be detrimental to your Goldfish’s life.


The main thing to think of with plants, or if you want to add any ornaments to your tank, is how they will affect the purity of the water. The other factor to take into consideration is the types of plants that will survive in the water conditions.

Goldfish will particularly be well placed with plants such as Pennywort or Hornwort, Cabomba, Java ferns/moss, or Pothos. These particular plants will do well in cooler water temperatures and do not need constant light and heat lamps, which will be perfect for your Goldfish.

(Have you ever thought about keeping Goldfish and glofish together?)

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Molly Habitat

Mollies can be found in freshwaters mostly around Mexico and Southern parts of North America. Mollies are found in different water types, including brackish, salt, and coastal waters, depending on what particular mollies you acquire.

They can be found in shallow waters, so they are able to maintain survival in low oxygen environments and will hide in underwater foliage to hide from predators.

Molly Tank Requirements

Tank Size

Depending on what type of Molly fish you want determines the size of the tank you will need. The other consideration is how many Molly fish you are starting with. A school of Molly fish will commonly need 20 gallons of water; however, for species such as the Sailfin Molly, they’ll need a minimum of 30 gallons as they are bigger fish.

Although Mollies are required to be in schools, ensure that you are not overcrowding your fish tank, as this can lead to aggression between schools. This will become stressful for all fish in the tank, and you risk losing them.

pH level and temperature

It’s really important that you keep a constant, steady pH level for your fish, as changes cause them stress! Molly fish thrive in water with a pH level between 7.5-8.5, as these particular fish prefer harder water conditions.

Temperatures of water for Mollies should roughly be between 21.5 degrees Celsius to 28.5 degrees celsius. Although they are known for their adaptability, it’s important to be accommodating to your fish rather than vice versa. Being consistent with both the pH level and temperatures will benefit your Molly’s well-being greatly.

Plants And Ornaments

The best thing to do for your Molly tank is to fill it with greenery! Mollies will hide in the plants if they feel threatened by a predator, which is perfect in a community tank. However, plants also provide reproduction and spawning relief.

If you want to put gravel in the tank with Mollies, that is also fine! However, we want to keep a fine, sandy texture as this is where your fish will rest at night! By all means, incorporate rocks and ornaments that they’ll be able to rest on, too, as this will double as hiding places for them.

(You could also try keeping mollies or Goldfish with guppies as well!)


Just like the other discussion points, diet is included as one of the most important things to understand when keeping fish. Just like all other animals, fish are in need of a well-balanced and varied diet to grow to their optimal size. Their diets should match what they would find in the wild but may include fish pellets that contain any vital nutrients also needed.

Goldfish Diet

Goldfish are omnivorous fish, which is great as they can be fed a variety of things! One thing to be aware of with Goldfish is that they have a tendency to eat whatever fits in their mouths! This is a problem for anyone wanting to keep small fish or crustaceans in their community tanks.

We recommend feeding your Goldfish two to three times a day and no more than what they can eat around the two-minute mark. This is to stop any build-up of grime and foul food in your tank!

In the wild, Goldfish would have free reign on their food which would include insects, plankton, crustaceans and plants.

If owning Goldfish, it would be best to replicate the wild diet, but you may also incorporate any Goldfish flakes or pellets from aquatic/pet stores. Just try not to stick to the same foods constantly. Change it up every now and again, as Goldfish may get bored of a diet that remains the same.

(Goldfish and minnows can often make great tank mates too.)

Molly Diet

Mollies are small fish that require feeding around twice a day. They are omnivorous fish, just as Goldfish are, so you have plenty of options as to what you can feed them!

As with other fish, you are able to buy specific fish food for Mollies but use this as well as other foods to provide a varied diet to keep your fish happy!

We recommend feeding your school of Mollies a pinch of food at a time as they have very small digestive systems, and their stomachs are about the size of their eyeballs! To avoid overfeeding, you may also try the ‘only feed them what they can eat in five minutes’ method.

Overfeeding causes problems for your Mollies’ health as well as dirtying the tank, which may lead to disease and parasites.

Along with food flakes or pellets, Mollies may also eat small pieces of peeled green vegetables. This also includes greens like spinach, lettuce, and cucumber. You may also give your Mollies bloodworms, brine shrimps, or krill.

How To Make It Work?

After taking everything into consideration with how these two species of fish live, it would be correct in stating they shouldn’t live in the same tank together.

These fish have different requirements in their environments, down to basics like temperature. Also. cohabiting may make Mollies aggressive, which isn’t fair for either of the fish.

(Do you ever wonder if you can keep Goldfish and shrimp together.)


Separately, Goldfish and Mollies would be fantastic pets for a new or existing fish keeper. They’re interesting fish that require different types of habitats. However, if you’re interested in keeping them, it would be wise to do so in their own separate tanks.

By following this short guide on how best to look after these two types of fish, you can be reassured you have the right information to have healthy, happy fish!

If you are looking for advice on fish for a community tank, we have compiled further advice on what fish are the most and least suitable!

Ultimate Betta Fish Care Guide
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