molly fish

Molly Fish Information

Meeting the Mollies: Molly Fish Intro and Info

Mollies are simple, unassuming fish that do not require much.

They are found in many aquariums and fish tanks throughout the world. Their peaceful nature makes them the ideal tank mates for other fish.

Where did Mollies come from?

Mollies originated in the waters off of Mexico to the South American oceans. It’s not unusual to find these little fish swimming in warm waters in Central America.

The U.S. is seeing an influx of Mollies in the lower southern gulf regions. These fish have been found in drainage systems as well as rivers that feed into the gulf waters.

There are 12 varieties of Mollies, each with distinguishing characteristics and traits.

Short finned Mollies, in general, are an easy fish to raise. They are not demanding of their keepers, and will live quite happily in a 10 gallon tank.

the caribbean map

 Sailfin Mollies, on the other hand, can be a bit more difficult to keep, if only because they are the larger of the species.

Types of Molly Fish

The Molly has a few other names that people use when referencing this little fish.

  • Black Molly
  • Black Lyretail Molly
  • Black Sailfin Molly
  • Pointed Mouth Molly
  • Short Finned Molly
  • Mexican Molly
  • Golden Sailfin Molly
  • Marble Lyretail Molly
  • Platinum Lyretail Molly
  • Piebald Molly
  • Ghost Pearl Molly
  • Gold Dust Molly
  • Red Sunset Molly
  • Dalmatian Molly
  • Balloon Molly
  • Gold Doubloon Molly
  • Harlequin Sailfin Molly

The scientific name for a Molly is Poecilia Sphenops.

What are Mollies used for?

Mollies are used as filler fish for fish tanks worldwide. They are very easy to care for and great for beginner fish hobbyists.

These fish are also the number one feeder fish because of how fast they grow in size.

Adaptable and Easy to Care for

Mollies are very adaptable to changing environments and have been seen in caves, freshwater areas, and in mangroves living in seawater.

The Molly seems to thrive in salty, briny water which is why they have been found in caves. The high mineral content of cave water attracts the Molly.

Mollies are capable of living a long time! In the wild, they live up to 5 years. In captivity, they tend to live 3-5 years.

Great Beginner Fish

Whether you are a first-time fish hobbyist or a seasoned aquarist, Mollies are hardy fish that are great to raise and care for!

There are so many different types of Molly Fish  and Now that we know a little more about Molly fish let’s get ready to set up a great environment for our Mollie​​​​s.

Molly Fish Tank Size

The first item to check off on your quest to raise Molly fish will be to determine a tank size. Both species of Mollies, in order to thrive and grow well, should ideally be housed in at least a 29 gallon tank.

The benefit of a larger tank is the water stability. ​

won’t have the sudden quality changes in the water environment that smaller tanks suffer from. This will help to ensure the health of your Molly fish.

Filtration For The Molly Fish

Filtration will be the second item you want to look into.

 The better the filtration, the better the water quality you will be managing. Mollies actually prefer their tank to be over-filtered, not because they are a messy fish, but rather because the hybrids can be more susceptible to disease.

The best filter to purchase is a canister filter.

However, knowing that not everyone has a money tree in their backyard, purchasing a high quality filter that hangs on the tank will work as well.​ No matter what you choose, the one that offers excellent filtration, is very durable and long lasting, will be the one you want for your tank.

On a side note, there are some people who feel that Mollies need salt because of the time they spend in brackish water in the wild. In a human kept tank, salt is not a must have. You will need to determine this on a case by case, or fish by fish basis. Mostly it stems from some hybrids and their susceptibility to disease.

The thought was that the salt would help to keep disease at bay.

Food For Mollies

Next on your checklist is food. What food is best for your molly community? Feeding Mollies can be like feeding yourself, if you are an omnivore.

 First off, purchase a high quality flake food. This should be the staple of your fish feeding routine.

They will also thrive on fresh zucchini coins, cucumber medallions and shelled peas that have been blanched.

golden sailfin molly fish

Of course, not everyone has the time to do this on a daily basis, we understand that. So what do you do instead?

 You can purchase a spirulina based flake diet can help with supplementation.

Heating Molly Fish Tank

Heating the Molly fish tank will be the next item to look into. Because they are a tropical fish, you will want to purchase a decent heater to keep the water at a constant temperature. 

If they get too cold, they are more susceptible to disease. Keep the tank at a temperature between 75 and 82 degrees F.

You will want to research a heater that is rated at 5 watts for every gallon of water that your tank holds. This will ensure that the heater can work as it is designed and lasts longer.

Cleaning And Water Changes For Molly Fish Tank

The last item on your must do checklist, water changes and gravel cleaning.​ This is very important to keep the tank and your fish healthy. But, you ask, doesn’t the filtration system do all that?

Yes, it does, in its own way. However, nothing is perfect. Debris and fish waste falls into the gravel and gets trapped, something the filter can’t take care of. So we have to do some further cleaning to help the filter out.

How often you clean the gravel and change over the water depends primarily on the size of your tank and how many fish are in it.

There is a wonderful tool sold in pet stores and online that does the job easily and efficiently. It’s a water changer/gravel vacuum. How do I know it’s wonderful? I’ve used one for years. I love it and can’t recommend it enough to fish keepers.

Molly Fish Community Tank Mates

So on to getting the tank pretty and fun. What fish will work best with your molly fish? Well, you are in luck because Mollies like to be in a community.

Because they are laid back, it makes them easy to get along with. The best fish mates to have are other live-bearing tropical fish.

There are several breeds and species that will do well. 

Here are a few fish that make great Molly fish tankmates:

  • Tetras
  • Danios
  • Angelfish
  • Guppies
  • Platy
  • Gouramis
  • Swordtails
  • Female Bettas

Whatever you choose, follow this simple rule of thumb of one inch of fish per gallon of water.

So that if you have two mollies at four inches each and two others at say, seven inches together, that would be a minimum of a 15 gallon tank. 

 Whether you add more or keep your fish community small definitely depends on how often you want to clean the tank. More fish equals more waste.

In the end, it also depends on the aesthetic factor. What fish you choose to keep in your tank, allows you to be free in choosing colorful combinations.

Always keep in the back of your mind the size of tank and how often you want to clean. What species will go well together based on feeding, size, and personality.

We wish you happy fish keeping.

Scroll to Top