Molly fish: Types, Feeding, Breeding, reproduction and care

 Molly fish, or just molly, are tropical fish that belong to the Poecilidae family. These fish are very common in home aquariums because they are easy to care for and are the ideal choice for those who are beginning to venture into the world of aquarium hobby.

Mollies are traded in many countries as an ornamental fish, and within the molly category three common species can be found Black molly ( Poecilia sphenops ), giant fin molly ( Poecilia latipinna ), and veil molly ( Poecilia velifera ).

Characteristics of molly fish

Here is a technical sheet that summarizes some general aspects of raising molly fish. However, we must emphasize that there are some particular criteria depending on the variety of molly that you are raising.

– Common name: Molly, moli, or Mexican topote

– Scientific name: Poecilia sphenops (black molly), Poecilia latipinna (giant fin molly), Poecilia velifera (Yucatan molly)

– Temperament: Calm

– Water temperature: Range from 19 to 30 oC, optimum from 24 to 26 oC

– Water pH: 7 to 8.2

– Water hardness: 11 – 30 dH

– Diet (feeding): Omnivore

– Size: from 6 to 20 cm, depending on the species of molly

– Life expectancy: 3 – 5 years

types of molly fish

Molly fish are available in different colors (orange, silver, black, green, gold), depending on origin and sex. Some varieties are the result of crossing P. sphenops with P. latipinna, these two species are easily crossed in the fish tank.

black molly fish

The black molly or Molinesia black ( Poecilia sphenops ) has an entirely black coloration. It reaches maximum sizes of 6 cm; however, some varieties can reach 12 cm. The black molly is distributed from Colombia to Mexico, in fresh and brackish waters.Poecilia sphenops has a normal dorsal fin.

sail molly fish

The sail molly ( Poecilia latipinna ) is naturally distributed on the Mexican Atlantic coast and the southern United States, it can reach a size of 15 cm. It is characterized by the fact that the males have a sail-shaped dorsal fin, and much more rectangular in shape than the common molly.

Poecilia latipinna has 18 or 19 spiny rays on the dorsal fin, which is spread out like a fan in males. Sail mollies grow best in brackish water.

Candle mollies are the most attractive and come in many varieties with different color variations.

Mexican sail molly fish

Poecilia velifera also known as Mexican candle molly or Yucatan molly is endemic to the Yucatan Peninsula of Mexico. The giant candle molly is rarer and more difficult to breed.

The Mexican sail molly has the larger shape, color, and dorsal fins in males that make them difficult to distinguish from the sail molly, but the fins of P. velifera differ slightly, they have small dots.

The Yucatan molly has a natural body color usually green with dark spots, and an albino line also exists.

How to distinguish the species of molly?

Today, almost all mollys traded for ornament are hybrids of the species black molly ( Poecilia sphenops ), giant fin molly ( Poecilia latipinna ), and sail molly ( Poecilia velifera ).

The identification of wild varieties is easier and you can use the following criteria:

a. fin size

The fin is one of the ways to distinguish the mollys. Molly fish are classified into two groups:

– Small fins: Includes the common molly

– Large fins: Includes sail types.

b. Dorsal fin location

In sail mollies the dorsal fin is situated in front of the anal fin, while in common mollies this fin starts behind the anal fin.

 c. Number of dorsal fin rays

This feature is used to distinguish between sail mollies, P. latipinna having about 14 rays while P. velifera will have about 18 rays.

How to reproduce molly fish?

Mollies are viviparous and very prolific. Also, males and females are easy to distinguish, the male is smaller and has the gonopodium, which is the reproductive organ. These fish begin their reproduction at the age of 4 months (Divya, 2018).

Reproduction of mollies is very simple, as long as they are provided with the right conditions. Rasanjalee and Dissanayake (2019) recommend a ratio of 3 females for every 2 males, to avoid fights and that females are not harassed; likewise, vegetation should be included.

Importantly, research by Schlupp et al (2010) established that female common molly ( P. sphenops ) had a preference for male mollies that had whisker-like filaments on their faces. The researchers indicate that this "whisker" on the male molly could transmit tactile signals to the female molly.

Another curious aspect, according to Palmer and Hankison (2015) is that the wavelength of ultraviolet light seems to influence the female candle molly ( P. latipinna ) in the choice of the male molly, so you must be careful in choosing the lighting your aquarium

The male molly fertilizes the female internally through his gonopodium. In this regard, it is important to note that Scherer et al (2018) concludes that the size of the male molly fish influences reproductive success, obtaining more offspring; however, it has no effect on the quality of the larvae.

The female molly is capable of saving sperm from a single copulation to produce up to nine births. Pregnant mollies are recognized by a black spot anterior to the anal fin.

The female molly produces 20 to 150 larvae 1-12 mm in length after six to eight weeks of gestation, depending on temperature. It is important to separate the pregnant female to a separate tank, as adult mollys prey on the young.

Durgude et al (2020) determined that for cage culture of mollies, in order to achieve the highest rate of fingerling production, the most suitable density is 50 fish/m2 in a sexual ratio of 4 females to 1 male and for a period of 90 days.

Selective breeding of mollies

Most commercially available ornamental fish mollies were obtained through selective breeding and are hybrids.

During all these years of selective breeding, a variety of colors and patterns have been produced, ranging from the black molly, the Dalmatian molly, the orange molly, etc. The albino coloration comes from the candle species.

Body shapes and fins have also been selectively bred. Molly fish now have a more robust body shape, lyre-like tails, among other features.

The most frequent crosses are between P. sphenops and P. latipinna , resulting in lyretails, sunfish, and flagfish.

A unique variety is the balloon molly (Balloon Molly). This fish has a short and round shape. Parenting causes an unnatural curvature of the spine. However, this form causes great damage to the internal organs.

What do molly fish eat?

Mollies are omnivores, which means that in their natural environment they consume detritus, worms, crustaceans and benthic microalgae and insects.

If you keep some molly fish in your fish tank, they accept any type of food: live, dried, scales, etc; however, a plant-based food source is necessary for a balanced diet.

The baby mollys (larvae – fingerlings) feed consists of dried food and small water fleas, brine shrimp ( Artemia ) nauplii, tubifex or bloodworms . In this regard, Sumithra et al (2014) report that a mixed diet (rotifers, cladocerans and copepods) is adequate to achieve high growth and survival rates in molly fish larvae.

A practice that has been spreading is the use of probiotics in fish feed. Ahmadifard et al (2019) determined that the use of Artemia enriched with Bacillus subtilis (1 x 10 5 CFU/mL) improves reproductive parameters, intestinal microflora and resistance to pathogenic bacteria of candle molly ( Poecilia latipinna ).

Pour et al (2014) recommend supplementing mollyfish artificial diets with garlic (15 g/kg) to improve growth performance, feed utilization and body composition.

The recommended feeding frequency for mollies is 2 to 3 times per day, each time they are given small amounts of food.

Molly Behavior

Mollies have a peaceful and sociable behavior with the rest of the fish; however, adult males can become territorial with other aquarium fish, this is the main reason why mollys can display aggressive behavior towards other ornamental fish species.

Mollies are appropriate for a community aquarium and are suitable for breeding with guppies, platies and swordtails.

Diseases that affect molly fish

Mollies seem to have a lower resistance to infections by fungi or by ciliates such as Ichthyophthirius multifiliis (Ich), compared to other fish. Fungal and ciliate infections can be prevented and treated by adding 1 to 1.5 teaspoons of salt (without iodine) to the aquarium.

Maceda and Cable (2014) found that sea salt baths (10 g/L) were more effective against Ich.

Another common disease is the so-called "Molly's disease", caused by the bacterium Flavobacterium columnare , which causes deformation in the spine of the fish.

Molly fish are subject to the same diseases as other tropical fish. The best way to prevent illness is to provide your molly with the right environment and a well-balanced diet.

molly fish care

– The ideal size of the aquarium or fish tank for mollies (one male and three females) is from 40 liters. For candle mollies, aquariums of at least 100 liters are required.

– Wan et al. (2014) found that mollies can be farmed in brackish water (3 to 6 PSU).

– Frequent water changes should be made, at least every week and accompanied by siphoning, in quantities equal to 30 or 40 percent of the aquarium's capacity.

– Plants that can be planted in the molly fish tank include: Elodea , Ambulia , Limnophila sessiliflora , Vallisnerias, Didiplis diandra , Ludwigia repens , among others. The tank should mimic the natural habitat of the mollies, which will create less stress for the fish.

– Zutshi and Singh (2020) determined that a photoperiod of 18 hours of light and 6 hours of darkness is effective in inducing growth and gonadal development in mollyfish (P. sphenops).

– Valencia et al (2016) in their research conclude that the growth of molly pups is favored in the presence of salt, recommending sea salt concentrations of 13‰ for black molly and 18‰ for fin molly giant.

– Prada and Velmurugan (2020) concluded that the photoperiod is an essential factor to improve the color of P. sphenops ; however, the orange balloon molly develops chronic stress when continuously exposed to LED lights.

– Larvae of the candle molly (P. latipinna) grow best in white light under a photoperiod of 12 h light and 12 h darkness (Shahbazi et al., 2018).

conclusion

If you are starting to raise ornamental fish, without a doubt molly fish are for you. These fish require only basic care, and can be the start of a very exciting hobby.