Molly Fish: Description, Types, Pictures, & Fun Facts

Molly Fish: All You Need To Know

The Molly (Poecilia) is an omnivorous fish that belongs to the Animalia family, phylum Chordata, class Actinopterygii, order Cyprinodontiformes, and family Poeciliidae. Its genus is Poecilia.

The molly can grow up to 2 to 4 inches long and weigh up to a few grams, with a lifespan of up to 3 to 5 years. Molly are freshwater fish that feed on small algae, insects, and bloodworms. Molly is preyed upon by giant water bugs, American alligators, snowy egrets, bullfrogs, and raccoons.

The distinguishing characteristics are their large-sized fins and the bear’s live young. Physical characteristics include green, blue, orange, black, red, yellow, brown, and white colours, with scales on the skin.

Molly fish come in more than 40 different species, but only a few of them are commonly kept in aquariums. Molly fish are American fish that are mostly found in the wild in North and South America.

Molly fish were first recognised by naturalists in the 1820s. The molly has been a popular fish to keep in freshwater aquariums since before 1899. Because all molly fish species may hybridise with one another, they come in a variety of colours, patterns, and combinations.

Because most species in the wild still have huge populations, this fish is not considered endangered. They are technically omnivores, but they eat mostly plant matter.

Five Incredible Molly Fish Facts!

1. Male molly fish have a unique anal fin called a gonopodium, which is substantially smaller than female molly fish. Female mollies utilise this rod-shaped organ to deposit sperm, which they can keep for long periods of time.

2. Molly fish have been selectively bred throughout the years, resulting in a stunning assortment of colours and patterns. The form of this fish’s dorsal and tail fins also vary significantly.

3. Hybridized molly fish first appeared in the 1920s, and they immediately gained popularity among aquarium aficionados. Despite the fact that hybridised mollies are common in artificial habitats, they are rarely encountered in the wild.

4. Mollies, as opposed to schooling fish, or shoaling. This implies that, while they frequently travel in groups, they do so for social reasons rather than to go in specific directions.

5. The common molly, black molly, white molly, sailfin molly, and Mexican molly are the most common molly fish available for aquariums. These species are also the most numerous in the wild.

Molly Fish Classification and Scientific Name

The molly fish is a member of the Poeciliidae family of the genus Poecilia. Poecilia is a Latin word that means “many colours.” The term “poikilos” comes from the Greek word “poikilos,” which means “many hues.”

This is due to the fact that the colours and patterns of these fish vary significantly. Molly fish have numerous scientific names depending on their species. Poecilia sphenops, for example, is the scientific name for the common, or short-finned, molly.

The name “Sphenops” means “wedge appearance” and alludes to the stubby, wedge-shaped fins of this species. Poecilia latipinna is the scientific name for the sailfin molly, popularly known as the topsail molly.

The name “Latipinna” means “wide fin,” which describes the morphology of this species’ fins. Finally, the scientific name for the Mexican sailfin molly is Poecilia velifera. The name “Velifera” means “sail-bearing,” referring to the species’ one-of-a-kind sailfin.

Various Molly Fish Species

There are no precise numbers of current molly populations in the wild. This fish, on the other hand, is not considered endangered. Various species of mollies have different population numbers, and the sailfin molly is very common in the wild and is not considered endangered.

Although there are numerous mollies in the wild, many more are kept in aquariums. Several molly fish are thought to be many generations away from being released into the wild after being raised in captivity for years.

Because these fish are prolific breeders, their numbers are unlikely to diminish. In fact, because the gestational time of these fish fluctuates depending on variables like water temperature and salinity, climate conditions can have an impact on their capacity to reproduce.

Molly Fish Appearance and Behaviour

The common molly has a drab, silvery tint in the wild. Mating males have a greenish-blue tint to their bodies, which contrasts with their light grey bodies. Many mollies have rows of dots on their flanks, backs, and dorsal fins.

These areas might get so numerous that they resemble one huge design. Molly fish have chunky, thick-set bodies, rounded fins, tall, angular dorsal fins, and pointed heads and mouths in the majority of species.

Their upturned lips are meant to assist them in skimming the oxygen-rich top layer of the water. Their tails have a convex shape. Mollies can reach a length of 20 cm or more in the wild.

The majority of molly fish, on the other hand, are between 5 and 13 centimetres in length. Male mollies are typically smaller than females, while female mollies have rounder bodies. Male mollies have gonopodiums, which are one of their most recognisable features.

These are thin copulatory structures that double as specialised anal fins. Gonopodiums, which resemble rods, are utilised to transfer sperm into female mollies throughout reproduction.

Mollies, unlike many other fish, do not migrate in schools; instead, they travel in shoals. Multiple fish congregate in a shoal for social reasons.

They do this in a school to move in the same direction. The molly is one of approximately one-quarter of all fish that shoal their whole lives. They normally shoal in groups of hundreds, with a male-to-female ratio of one to two.

Mollies are top feeders who utilise their upturned jaws to feed on oxygen-rich surface water layers. As a result, they are tolerant to low oxygen levels and may survive in them. Mollies are active swimmers, despite their gentle nature.

Male mollies may be aggressive at times, and they have been known to chase females forcefully. Adult mollies frequently prey on young mollies since they do not give parental care to their offspring.

Mollies are diurnal, meaning they are awake during the day and sleep at night. Males tend to develop hierarchies, making them ideal communal fish.

Molly Fish Distribution, Population, and Habitat

Mollies are a kind of American fish that may be found in the wild in North and South America. They have, nevertheless, been adopted in nations such as Japan, Taiwan, Singapore, Israel, and even areas of Eastern Europe in recent decades.

Molly fish prefer shallow surface waters to dwell in. They are frequently found in coastal streams with little vegetation in the wild. These fish, on the other hand, have been shown to thrive in lakes, estuaries, deltas, swamps, ponds, marshes, and even ephemeral locations such as roadside ditches.

To avoid predators, they prefer to hide beneath floating plants or near buildings. They like water with a pH of 7.5 to 8.5 and a temperature of 64 to 82 degrees Fahrenheit. Mollies come in a variety of shapes and sizes, and they may be found in a variety of habitats.

The common molly, for example, may be found across Mexico and northern South America. The sailfin molly may be found in the Gulf of Mexico and throughout the United States’ southern coast. The Mexican molly is found largely in the coastal Yucatan region of southeastern Mexico.

Molly Fish Diet

Molly fish are technically omnivores, as they eat both plant and animal matter, as well as crustaceans, insects, and worms. However, because their meals are largely comprised of plant matter, these fish are effectively herbivores. Mollies like algae, but they have been seen to devour large amounts of other phytoplankton.

Molly Fish Predators and Prey

Mollies are not at risk of becoming extinct. The IUCN Red List of Threatened Species does not list the Mexican molly, while the common molly is classed as data deficient. This signifies that there isn’t enough information to establish whether or not the fish is endangered.

Most species, however, are thought to have large, stable populations in the wild. The sailfin molly is classified as Least Concern, which indicates it is unlikely to become an endangered species in the near future. Larger fish provide the greatest threat to the molly in terms of predators.

Because many molly species, particularly male mollies, are tiny, they are easy prey for bigger fish like largemouth bass. Fish may be hunted by aquatic birds, aquatic insects, amphibians, reptiles, and even mammals. Because mollies are surface feeders, this is especially true.

They must emerge to feed, despite their preference for hiding behind foliage and other objects, and this is when they become susceptible to predators. Giant water bugs, American alligators, snowy egrets, bullfrogs, and raccoons are among the molly fish’s other predators.

Mollies are also prey to other mollies on rare occasions. Although these fish are not violent, they are known to fin-nip, which is a common problem in aquariums. Young mollies must be kept away from males in aquariums because their fry are vulnerable to being attacked and devoured by male mollies.

Molly Fish Reproduction and Lifespan

Male mollies deposit sperm into female mollies via gonopodiums, which are specialised anal fins. Female fish are fertilised internally and have the ability to retain sperm for up to a few months. This adaptation ensures that populations remain strong even when male mollies are frightened away from the group.

Molly fish are prolific breeders with 28-day gestation cycles and often 50 to 100 live fry every period. However, depending on the temperature of the water, gestation times may vary. Females can produce live fry every 30 to 40 days or so, with females accounting for 70% of the fry.

Male mollies are known to chase female mollies aggressively, therefore keeping at least two females for every one male in an aquarium is beneficial to females. Mollies are live bearers, which means rather than laying eggs, they give birth to live fish.

Mollies achieve sexual maturity at a young age, allowing their populations to expand quickly. Molly fish live for roughly a year in the wild after reaching sexual maturity. In aquariums, however, these fish may survive for an average of three years, with some living for as long as five years.

Male mollies have a greater death rate than females, which is mostly due to their lower size, which makes them more vulnerable to predators. They do, however, have a higher risk of contracting illnesses.

Young molly fish must fend for themselves in the wild right away. After they are born, their parents do not offer any kind of care for them. Because these fish may hybridise with any other molly fish species, selective breeding of these fish is quite popular.

Hybridization of molly species has resulted in a great variety of colours, patterns, and tail forms throughout the years, which is one of the reasons these fish are so popular in aquariums.