Molly Fish Species Profile, Types and Care Guide

In the Poeciliidae group, Molly fish, or just mollies, are freshwater fish from the genus Poecilia. All the varieties in this species are mollies lacking for the Endler’s livebearer. These fish belong to the Americas, but their habitat can fluctuate significantly.

An impressive detail about mollies is that, similar to guppies, and they are livebearers. This indicates that they continuously endure their eggs inside their bodies and can furnish birth to exist young straight into the water.

They are a very successful association of fish. The greatest varieties are healthy and easy to care for, composing them excellent for newcomers. They work properly in peaceful association aquariums. If retained in a healthful climate, an association of mollies will increase and live up to 5 years.

Molly Fish Species Facts

  • Family: Poeciliidae
  • Care level: Easy
  • Lifespan: Up to 5 years
  • Size: Up to 4.5 inches
  • Color: Various colors
  • Diet: Omnivores
  • Minimum tank size: 10 gallons
  • pH levels: 6.7 – 8.5
  • Water hardness: 20-30 KH
  • Temperature range: 78 – 82 ℉ (25-27 ℃)
  • Compatibility: Other calm community fish
  • Tank set up: Fresh water tank with plants

Typical Behavior

Mollies are shoaling fish, so they require being in the appearance of others to exhibit comfortable. They are a nonviolent bunch but can manifest indications of offensive when crowded or enclosed by threatening tank mates. You should retain a collection of at most trivial four fish at the very least, and an even bigger group is more beneficial if possible!

Mollies are energetic and pleasant, so they experience schooling synchronically. A shoal should be predominantly female since males are identified to despoil and stress females. They are one of the most obvious species for breeding at the homestead, so they are excellent for aquarists starting their first breeding container.

Some people confuse Molly Fish breeding behaviors as symptoms of invasion. When you have a mix of both members, you may recognize the males following the females. This isn’t aggressive, and it is just a portion of their courtship. It’s easy to detect personalities in an effective fish like these. Observing them for a while will promptly make you attached as you regard their differences.

You may also check: Neon tetra facts

Appearance and Types

Many molly fish varieties are much related to the standard molly (Poecilia sphenops). The principal variations are colors and patterns, but sizes and shapes can vary too. While there are numerous species, most have a related shape and body style to the general molly.

These fish have a smoothed body with a triangular-shaped head. The standard molly has a flattened body, and it’s tall in the middle and narrows towards a point at the mouth. At another end is the caudal fin, a large fan that can be transparent or colorful. The dorsal fin can be supported as a fan, favoring the caudal fin or embellishing toward the body.

Sexing these fish isn’t too arduous, and they are comfortable to mate. Females have an anal membrane that expands into a fan, whereas a male is pointier. Females are more extensive, too, potentially approaching 4.5 inches, and males produce to 3 inches. Pregnant females will resemble even larger, and their bellies expand to be much bigger than additional females.

Here’s a summary of a few favorite mollies for residence aquariums:

Black Molly Fish

These fish are black all over. Distant from that, they’re essentially the equivalent as the standard molly.

Sailfin Molly

This variation is produced in several distinctive colors and patterns. Its most specific specialty is the extensive dorsal fin that follows the head to just before the caudal fin.

Lyretail Molly

Just similar to the sailfin molly, the lyretail reaches out because of its fins, but this moment it’s the caudal fin. The top and bottom of the fin narrow into points that trail behind the rest of the fish.

Additional popular mollies include the Dalmatian, Balloon, Red, White, and Orange.

Habitat and Tank Conditions

In the wild, a molly’s habitat can vary. They have adapted to numerous water conditions, including toleration to brackish waters and great hydrogen sulfide levels.

They are essentially discovered in the shallow portions of rivers and streams beyond North and South America. Here the substrate would be sandy with rocks and debris sitting on top.

Plants would be superfluous too, they essentially utilize these as shelter, but they’re also essential for a generation. The rivers are in tropical environments, so get a great supply of light for plant growth.

Tank Setup

  • Minimum Tank Size: 15 gallons or 30 for sailfin species
  • Optimal Tank Size: 20+ per 1 molly with an extra 3 gallons per additional molly
  • Optimal Tank Shape: Tall aquariums are ideal for mollies
  • Supported Filter Type: Any but go larger than you anticipate you’ll need

Extra Air Flow and How to Provide: Mollies do best with different air movements in the aquarium. Add in many air stones, one per 10 gallons ideally, to improve your mollies growth.

Mollies developed in captivity are related to an identical climate, so you won’t have to bother requiring a separate setup from another tank for fish with related water chemistry essentials.

Mollies are tropical fish, so they require their tank to be sustained at a warm, suitable temperature to keep them healthy and happy. They also require the balance of hard water and pH levels, whether you hold them in freshwater aquariums or brackish fish tanks.

Tank Mates

Molly fish are easy-going and versatile fish that can be the habitat with various species of fish. This is only if the tank is extensively suitable as numerous fish put into one small vessel will generate the mollies to enhance destructive towards the additional fish; however, this will not happen if put in a big place.

Mollies are pleasant fish and prefer to be retained with different mollies in a school. So when accepting a molly, you should consider getting further before supplementing in any different tank mates.

Mollies can be housed with top and middle residents and become on fittest with livebearers such as guppies, platys, swordtails, and endlers. These fish are comparable to mollies and are ordinarily retained by tropical fish partners; however, swordtails can cross-breed with mollies while endler’s can cross-breed with guppies.


Mollies are omnivorous fish that feed on algae, plant material, and small lobsters in the wild. Therefore they should also be provided a different nutrition diet in a house aquarium, including high-quality flake food, pellets, and exceptional vegetables as a continuation. They should be supported 1-2 times a day and only served as much as they can consume in 5 minutes unless any uneaten food will fall to the bottom and start to decompose.  This provides their digestive regularity a hazard to prepare the food.

Molly fish should be given this variety of food to provide them with the essential nutrients and guarantee health. Mollies can also be supported by functional foods such as bloodworms and shrimps, and these can be obtained at your local pet shop or online aquatic repository.

Mollies can be served vegetables, including shelled peas, cucumber medallions, and zucchini medallions. However, this can seldom be time-consuming; therefore, a spirulina-based flake or pellet can be an option to plant elements in their diet.


Mollies are some of the most powerful and more tractable fish out there. Just like any additional fish, the great idea is Mollies, a clean tank fish. It would be best to apprehend how to cleanse efficiently, including observing the water requirements and monitoring that ammonia and nitrites are at 0ppm.

Your fish will probably commence losing their color or improve worse health difficulties if water prohibitions are poor. Monitoring the water requirements will encourage you to circumvent relinquishing this point. Mollies may produce a disease called “molly disease” (or “livebearer disease,” or “shimmies”). This isn’t a condition because poor water situations generate it.

Affected fish will swim about less, wiggling and shimmying at one point. Monitor your water parameters and rectify any concerns; once conditions revert to normal, you should see developments in the health of your mollies.

In addition to molly conditions, they can arrange a spectrum of conditions prevalent in freshwater fish, such as itch and velvet. Retain an eye on your fish to recognize indications of the condition. Obvious indications constitute a loss of appetite, inactivity, spots, wounds, and color changes.

Cleaning the tank and changing up their diet are a couple of easy ways to diminish the severity of the disease. If the obstacles endure, there are procedures that you can purchase from storehouses.


Mollies are livebearers, which indicate their eggs improve inside their bodies to deliver the live fry. They are one of the most obvious fish groups to propagate in captivity and will mate repeatedly.

Increasing the temperature could somewhat support initiating mating, but don’t reach higher than 78°F. Males perform a courting exposure for the females; when the female is eager to mate, she will provide the male to generate her eggs. Seldom does the male attempt to “sneak-copulate” where he proposes an ignorant female from behind.

Females frequently prefer to mate with the most generous males. Later fertilization will take 35-45 days before the young are released, and larger females could deliver up to 100 juveniles.

The young require to be distributed from the adults, or they will become eaten. One alternative is to place pregnant mollies in a breeder’s box before they deliver birth, the young are easy to leave the box through small holes, but the adults linger confined.

Are Molly Fish Right for You?

Mollies are surprisingly interesting fish that appear in an enormous diversity of colors and various fin shapes. They’re healthy fish that’s even more powerful. Given the proper restraints, they can live for 3-4 years and generate thousands of babies in their lifetime.

So it’s essential to determine whether you’re just going to let adults feed the fry, distribute the fry and support them and what you’d do for houses for the fry that execute it. It’s also crucial to recognize that mollies become quite a bit bigger than various inhabitants fish.

You’ll require a larger tank to retain this species since they settled off so much waste. Overall, I believe Mollies obtain a great pet if you have the right restrictions to house them, and they have curious characters that you’ll find considerably charming.

Things to Know More about Molly Fish

  • Male molly fish, which tend to be much smaller than female mollies, have a specialized anal fin called a gonopodium. This rod-shaped organ is used to deposit sperm in female mollies, which can retain it for extended periods of time.
  • The selective breeding of molly fish through the years has produced a dazzling array of colors and patterns. These fish also vary widely in terms of the shape of their dorsal and tail fins.
  • Hybridized versions of molly fish started appearing during the 1920s, and they quickly became popular with aquarium enthusiasts. Although hybridized mollies are abundant in artificial environments, they aren’t typically seen in the wild.
  • Mollies are shoaling fish as opposed to schooling fish. This means that although they tend to travel in groups, they do so more for social purposes than for traveling in specific directions with each other.
  • The most common varieties of molly fish that are typically available for aquariums are the common molly, the black molly, the white molly fish, the sailfin molly, and the Mexican molly. These species are also the most abundant to be found naturally in the wild.
  • Mollies are an unusual species in that they can live in anything from freshwater to saltwater like in the ocean. Most fish can only survive in one or the other.
  • Mollies have a huge array of coloring choices, thanks to specific breeding, hybridization, and the mere fact that they are intensely prolific breeders.
  • Molly fish are livebearers, not egg-layers, making them distinct from many of the other popular aquarium fish you might choose to keep.

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