Dalmatian Molly, in particular, and Mollies, in general, are amongst the most commonly sought fishes in the aquarium world today. Initially originated from the tropical freshwaters of the American continents, and voila! Currently, they are found almost in every country.

Quite often, when we hear the name ‘Dalmatian,’ it is no surprise to relate it to something else, and you know it, but let’s be clear and focus entirely on the marine one today.

Indeed, it is true that Dalmatian Molly fish has a borrowed name, but they didn’t do it on their own; we did it for a good reason, perhaps, to have a better harmony with them.

This article will substantiate most of the practical aspects of how Dalmatian Molly can be deeply intertwined to fulfill our desire to keep them at home.

General Description of Dalmatian Molly

Quick Reference
Scientific Name Poecilia sphenops
Common Name Mollies
Family Poeciliidae
Origin Central and South America
Lifespan 3 – 5 Years (Ex-Situ)
Size (Length) 3 – 7.5 cm
Type Freshwater Fish

Physical Characteristics of Dalmatian Molly

They are small to medium size fish of the Poecilia species. As the name itself defines it in the Greek word, “Poilikos” means “with lots of colors.” These species of marines are genuinely spectacular to gaze at it. Physiologically, they are very active creatures and love schooling.

Morphology and Identification

Dalmatian Mollies are classic examples of being self-explanatory with names in their identification and morphology. Let’s justify this sentence with more elements of their species.

  • Dalmatian Molly-The blackish coloration is distributed with uneven white spots on their entire body.
  • Dalmatian Lyretail Molly– The characteristic appearance of the former along with a ‘U’ shaped internally curved tail extremity.
  • Common Black Molly-They appear in charcoal black on the entire body.
  • Dalmatian Balloon Molly– They include all the above features and a rounded abdomen.
  • CreamsicleDalmation Molly-It has a light ivorycolor on the body with black spots.
  • Orange Dalmatian Molly-Orange surfacedotted with black spots.
  • White/ Siver Sailfin Molly– They can appear in both white and silver colors. The dorsal fin is large and radiates backward.
  • Black LyretailMolly-Entirely black with a U-shaped tail.
  • Black Sailfin Molly-Similar to Common Black Molly with modifications on the tail in U-shapes.
  • Balloon Belly Molly-The belly is spherical. They can occur in all types of colors present in mollies. This breed has developed from genetic mutation, specifically a dominant allele (gene) that causes the spine to be curved, making the belly bulge. They are perfectly healthy, and the cogenetic defects can be transmitted from both the male and female Molly to their offspring.
  • Gold Doubloon Molly– The initial half of the body is golden while the remaining part is black.
  • Harlequin Sailfin Molly– Typically, the dominant color is orange, but the fins are distributed with varied colors like white, black, and orange.
  • Platinum Lyretail Molly-Usually has a polished silvery body with dark fins.
  • Golden Sailfin Molly-The radiant golden color body is supplemented with the characters of a sail.
  • Wild Molly– They area non-hybrid variety that naturally occurs in the wild. Have a silver body with a relatively smaller dorsal fin, and light brown extremities.

Pro Tip: The lyre is a Greek stringed musical instrument. Consider taking a glimpse from the internet to better comprehend the name applied here.

Dimorphism in Dalmatian Molly Fish

The appearance of mature male and female Dalmatian Molly fish is notably distinguishable. The differences can be understood under the following parameters described below.

  • Color– Male are known to display brighter colors in comparison to females. These adaptive features help the male to attract females for mating.
  • Size– Females are larger than males.
  • Dorsal Fin– The fin present along the line of the vertebral column is relatively bigger in males.
  • Anal Fin– One of the most distinct features to differentiate them. A male has a unique modified sexual organ called ‘Gonopodium.’ This organ is present in the anal fin of males, and hence they appear more extended than the females.
  • Behavioral Pattern– Males are attention seekers, and to accomplish this, they swim ahead of the females to be noticed.
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Expert Tip: Gendering can be done only after full maturity. The above-described headings are secondary sexual characters.

Habitat and Environment

Dalmatian Mollies are naturally hardy breeds of fishes that occur naturally in tropical fresh and saline waters. They can adapt to a diurnal range of heat and cold from 65°F to 82°F(a vast difference of 17°F), which is remarkable. They are known to be benthopelagic. Thus, they strive and feed on the bottom and occasionally on the mid and surface layer of water.


According to International Union for Conservation of Nature(IUCN), they are accorded the ‘Least Concern’ status. This is a boon for the aquarium industries and individual hobbyists in availing one of these species in any part of the world.


Depending on the location, one can easily purchase them anywhere between 2$-50$.

Authors note: Your nearest Aquarium store will be the best source of information on this.

Care Guide

Quick Reference
Food Habits Omnivore
Feeding Frequency 2-3 times per day
Temperament Moderately Peaceful
Breeding Season Non-Specific (Any time after maturity)
Gestation Period 28 Days
Maturity 4-6 Months

Food and Diet

It is safe to say that one doesn’t have to worry about their feeding habits because they are omnivores. Different kinds of fish feeds are available commercially, and most of them can be suitable for Dalmatian Molly Fish with slight modifications in the physical presentation.

Apart from commercial ones, your kitchen veggies are also another good source of complement. Irrespective of the feed, it is recommendatory to vary their diet so that the part of nutrient that is missing in one source can be compensated by other.

List of Food Items

  • Algae Pellets/ Flakes
  • Frozen/Live Shrimps
  • Frozen/Live Blood Worms
  • Blanched Vegetables-Spinach, Carrots, Lettuce, etc.

It is well noticed that live feeds are much more enjoyable for the fish to eat.

How Much Should You Feed Them?

The amount of feed provided to Dalmatian Molly will depend upon their size and maturity. Feeding them at regular intervals of at least twice a day is advisable. Typically, one can feed them as much as they can finish within 2 – 3minutes.

General Behaviour

Dalmatian Mollies are psychologically very social. Usually, they are docile, energetic, and harmless creatures. They can be seen swimming in groups most of the time around the tank and can even become aggressive when unsuitable tank mates or overcrowding occurs.


Dalmatian Molly is considered one of the most prolific breeders among the aquarium fishes. This ranking is based on the number of young ones it can produce within a short period. They are also easy to breed in an aquarium with fewer complications.

Physiologically, all species of Mollies are ‘Live-bearers.’ This implies that they do not lay eggs but instead give birth directly into the water. The eggs develop within the oviduct of the females after fertilization from the male sperm.

Generally, females allow the largest male to mate after a brief period of courtship by the latter. After a successful mating process, females undergo a gestation period of about 28 days.

Usually, a Dalmatian Molly female can give birth to somewhere between 20 – 150 young ones over many days, depending on the level of care and comfort during their breeding period.

Interesting Fact: The organ gonopodium present in males is similar to a penis!

How to Breed Them Successfully in Tanks?

As mentioned before, breeding Dalmatian Molly in your aquarium is not a difficult task. Let’s discuss some parameters in detail to double the chances of their multiplication.

  • Sex Ratio: Experimental data suggest that maintaining one male over four females is suitable for maximum breeding efficiency.
  • Tank Size: For every addition of 1adult Molly, an increase of 3 Gallons in the tank capacity is required so that they do not get over-crowded.
  • Temperature: Higher temperature with an upper limit of 82°F/27.7°C can induce them to mate more frequently.
  • Brooder Cage: This additional equipment is necessary if your stocking density is high or for a beginner. The brooder cage provides a platform where the young fry can escape while the mother is retained. Otherwise, it is also possible to quarantine the pregnant ones from the rest of the fish.
  • Lighting: A study conducted on reproduction effects in Dalmatian Mollies suggested that higher photoperiod increases their capacity to reproduce.
  • Adequate Feeding: As we know, Mollies can hunt smaller prey; if they are starved, the younger ones are in danger of being cannibalized.
  • Special Precautions: Many different varieties of Molly fish can readily interbreed amongst themselves. If maintaining a particular type is your priority, housing similar breeds together will be the trick to producing pure progeny. In addition, they can also successfully create crossbreed with other livebearer fish like Guppies.
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Care of Fry(s) from Birth Till Maturity

Live fry of Dalmatian Molly can be effectively reared with little expertise by keeping in mind a few points.

  • Feeding: There are no significant differences in the feeding habits of mature and juvenile fishes except that the size of the food particles should be smaller for the young ones. This consideration can be achieved by crushing the pelleted feed or opting for flakes. Likewise, you can slice veggies into smaller pieces.
  • Filters: The opening of the water filter should be small enough to prevent the fry from being sucked in. A sponge filter can be used efficiently instead of the conventional type.
  • Hideout: It is advisable to fill the tanks with lots of substrates to provide cover for the fry(s), mainly if housed with the adults; otherwise, maintaining a separate tank for adult Dalmatian Mollies and immature ones can be helpful.


All higher living organisms are susceptible to one or more diseases. The basis behind any illness or disorder prevailing in Mollies owes its origin to inadequate/ineffective management practices, which contribute directly or indirectly to stresses.

List of Stress Factors Contributing to Health Issues

  • Contaminated water can be a potent source for microorganisms.
  • Holding or touching them can be another good reason for stress.
  • If your Mollies are with other tank mates, they are most likely to compete for nutrients, oxygen, and spaces irrespective of the species involved.
  • Dalmatian Molly fishes produce a large amount of waste in the form of processed metabolites-nitrates, nitrates, ammonia, etc. These chemical build-ups during their physiological process are toxic to them if left accumulated.
  • The quality and quantity of feed you serve can also be another factor.
  • The lighting duration influences the ‘active’ and ‘passive’ status of your DalmatianMolly fish. Imbalances in these cycles can directly add more stress.
  • The pH level of the water changes due to the substrate and metabolites generated in the tank. Shifting pH towards the acidic side is highly stressful to them.
  • Despite being tolerant of temperature, the lower and upper threshold of temperature is the line beyond which stress or death can occur.

Keeping all the predisposing factors in mind, we need to be aware of certain disorders/diseases which are most likely to attack our Dalmatian Molly fishes. Let’sdiscussthem specifically in addition to some strategies to counter them.

Parasitic Disease

  • Ichthyophthirius multifiliis: They are commonly called ‘Ich’ or ‘White Spot Disease.’ It is an obligatory parasitic infestation that primarily targets the skin and gills of Mollies and other fishes and is highly contagious as it can transmit easily to tank mates.
  • Signs & Symptom: Lesions in the form of small whitish spots all over the body. This infestation might not be fatal, but as an infection, it will cause discomfort and stress leading to reduced growth, secondary infections, respiratory distress, osmoregulatory dysfunction, and a shorter lifespan.
  • Diagnosis: Tentatively diagnosing them can be pretty simple by visual observation.
    • Sea Salt (commercially available easily) @ 10g/Liter of water.
    • Metronidazole @10mg/Litre (Only if Secondary Bacterial Infections are involved).

Bacterial Diseases

  • Flavobacteriumcolumnare: This bacteria primarily affects the gills and other skin tissues. Mortality can be high in this infection.

Signs and Symptoms: It causes ulceration and necrosis of the gills and skin.

Diagnosis: This disease would require an expert for a successful diagnosis. However, observing the above-mentioned abnormalities in the DalmatianMolly, you can suspect this disease.

Treatment: Specific antibiotics based on proper diagnosis.

  • Aeromonas spp.:These bacterial species are almost ubiquitously present. One major cause of its outbreak is high stocking density and stress.

Signs and Symptoms: Fish infected with it can exhibit moderate to extreme symptoms like gills & fin lesions and skin ulceration.

Diagnosis: Similar to Flavobacterium infection.

Treatment: Eliminating the causes of stress along with specific antibiotics prescribed by your veterinarian.

Fungal Disease

  • These are broad categories of infections caused by non-specific organisms like fungi and yeast. These infections are manifested particularly concerning Dalmatian Mollies that have low immunity. Some common pathology associated with it includes fin rot and tail rot.

Miscellaneous Disorders

  • Dropsy: The causes of this abnormality are varied in many infections, including bacteria, viruses, and fungi.
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Signs and Symptoms: One thing you can be sure about this condition is the abnormal accumulation of water in any part of the body, and thus fishes appear bloated.

Diagnosis: It is based on symptoms. Specialized laboratory procedures can only determine causative agents.

Treatment: Quarantining and increasing their immunity with supplements.

  • Exophthalmia: This condition is characterized by the eyes popping out from the socket. Fishes with Dropsy can predispose this abnormality to emerge in them.
  • Scoliosis: It is a nutritional deficiency due to the shortage of Vitamin C, E, and Amino Acids in the body. Molly fish affected under this condition can show a crooked physique.

General Preventive Measure

The susceptibility of Dalmatian Mollies to most diseases can be significantly reduced by taking suitable measures. Steps to be taken as a precaution are discussed here:

  • Avoid over-crowding at all costs.
  • Tankmates should be considered carefully for maximum compatibility.
  • Feeding Molly Fish with Garlic (Allium sativum) Powder @ 15g/kg of feed has been shown to enhance growth performance, feed utilization, and body composition.
  • Mixed Herbal Supplementation @ 400 mg/kg body weight to increase their immunity.

Tank Management

Quick Reference
Min. Tank Size 28 – 30 Gallons
Water Temperature 65°F – 82°F
Lighting Required
Water pH level 7.2 – 8.2
Brooding Chamber Optional (For Pros) Required (Beginners)

Tank Parameters

  • Plants: Live aquatic plants and green algae will make your aquarium lively besides supplying fresh oxygen and rich food sources. These aquatic plants are available in most stores.
    Water tolerant branches of trees(Driftwood) can be placed obliquely across the tank to deliver more hiding spots for the young fry(s) and fingerlings.
  • Lighting: Besides providing your tank with better illumination, Dalmatian Molly fishes require better lighting than other fishes as they show positive sensitivity towards light during breeding.
    Options of lighting devices point towards an LED system available in the market, based on your tank requirements-size, shape, and color.
  • Substrate: Layering your tank with small to medium-sized gravel or sand can be a helpful addition besides supporting the plants and tank decors. Larger blocks of sea rocks/pebbles can provide good camouflage to the young ones.
  • Air Pump: One would need a high-capacity oxygen pump as Dalmatian Molly fish are rigorous feeders and waste producers. These are usually housed together as a community fish, so an efficient supply of fresh air is vital.
  • Water Filter: Opting for a sponge-type water filter is better for serving a dual purpose, i.e., usage for smaller fry(s).
  • Water Heater: This apparatus becomes necessary if one is from a cold geographicallocation as Dalmatian Mollies require a higher temperature, mainly to induce breeding, as discussed previously.
  • Décor: Artificial realistic plastic plants of all colors are easily accessible the market. One can add additional pigments to match the already colorful Mollies.

Tank Mates

Normally, the Dalmatian Molly Fish is peaceful and can make friends with many similar-sized fishes. Some are Guppies, Emperor Tetras, Cory Catfish, Gourami’s, and Loaches. Apart from fish, Nerite snails can be a great addition.

Water Quality Care

Ensuring the best water quality is essential as Dalmatian Mollies are usually kept in groups that amount to more waste excretion from respiration and metabolites. Some steps to be attended are listed; let’s find out.

  • Maintain the pH on the alkaline side(7.2 – 8.2) by monitoring them periodically.
  • Replace at least 20 – 30% of the water every week.
  • Use dechlorinated water as chlorine are toxic to fish.
  • Filtered water can be a better alternative to reduce impurities in the tanks.

Frequently Asked Questions

Can aggressive Dalmatian Molly be isolated?

Yes, it is better to isolate them to another tank for the safety of other tank mates. There are also chances that they may have become aggressive due to threats from other species or over-crowding. Consider this possibility before moving them away.

Is Dalmatian Mollie hard to keep alive?

Absolutely No. These are considered a ‘beginner’s fish’ because of their easy maintenance and high adaptability.

Can brown spots occur on Dalmatian Molly?

Logically it is possible to have brown spots on Dalmatian Molly since the different varieties of color patterns can occur due to interbreeding.

Is Bug-Eyed like Dalmatian Molly fish present?

This description is similar to Exophthalmia(protruding of the eyeball from the socket), and it is pathological.

How big do Dalmatian Mollies get?

According to some breeders, Dalmatian Mollies can grow up to 12 inches in length.

Can Dalmatian Mollies change gender?

They cannot interchange, though sexual dimorphism is seen only after complete maturity.

Finally, Should You Get Them Home?

Dalmatian Molly is among the few live-bearing fish unique in appearance yet readily accessible. As common as they may be, their aesthetic value in elegance is unmatched.

If you are a person who loves to count in numbers, these are the perfect choice as they can overwhelm you with their extraordinary multiplication capacity.

Lastly, they are friendly to your budget, a beginner’s perfect introduction to the aquarium, and an expert play ground for breeding experiments.

About the Author

Dr. Vituotsolie Kiso

Vituo Kiso is a budding Veterinarian and marine species enthusiast. He did most of his internships in several Pet Clinics, Wildlife centers, and Farms across India. He has a passion for learning new things and writings besides giving consultations and treating pets.

Career Highlights:

  • Almost 3 years of experience as a Veterinary Practitioner
  • Online Pet Health Consultant
  • Verified Tutor @studypool.com

Educational Highlights:

  • Attended Rajiv Gandhi Institute of Veterinary Education and Research
  • Currently learning Geography, History, Polity, Economics, Ethics, and International Relations.

Writing Experience

  • Wrote a White Paper on ‘The Aura of Pets and Humans’ for MaxCare Pets Inc.
  • Awarded the Best Article Writing on World Environmental Day 2020 on the topic, ‘Biodiversity.’

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