Molly Fish (The Ultimate Guide) – Types, Breeding, Tankmates & More

Mollies are one of those most prevalent types of fish in the aquarium. A great many people believe that there is just a single type of molly available in fish stores, yet one can find 3 different species of this fish.

In any case, a large portion of the mollies available in pet stores is hybridized due to the interbreeding of the 3 species. This is why it is difficult to figure out which species they started from.


If you, at any point, come across wild mollies in a fish store, they will typically originate from one of two fish categories.

The primary species are sailfin mollies (Poecilia latipinna) and short-finned mollies which are found in the Gulf of Mexico and the southeast United States. These are among the most widely recognized sort of mollies and are unbelievably prolific.

They have an unusually high resistance for salt water and have even been discovered living in the sea. There is a third type of mollies that is at times found in the aquarium, yet it is far rarer than either the sailfin or short-finned molly. The Mexican sailfin molly (P. velifera), is extremely hard to breed and keep in aquariums. However, it does well in open air lakes.

Let us now delve deeper into the Molly Fish Ultimate Guide to learn more facts about this type of fish in order to keep it healthy and provide it with suitable conditions!

Molly Fish Care – Mollies Tank Setup & Breeding (Video)

Keeping Molly Fish

Given below is a detailed note on keeping molly fish in aquariums.

Tank Size

The short-finned molly is not much demanding with regards to breeding. Most of them will joyfully live in a 10-gallon aquarium. In any case, if you genuinely need them to flourish, they ought to be furnished with roughly a 29-gallon tank.

Sailfin mollies, on the other hand, develop a lot bigger than their short-finned cousins and require a base tank size of no less than 29 gallons.

Bigger tanks additionally have the advantage of offering a more steady condition for the fish, since they aren’t as inclined to the sudden water condition variations as smaller tanks are.

As much as I would love to tell you that the optimum tank size for mollies is 10-15 gallons, it isn’t. Mollies are dynamic fish. This is why they would require a minimum of 29 gallons of water in their tank in order to flourish and remain stress-free.

Try not to keep the fish in little and swarmed tanks. They may stunted growth (many have been reported to grow only 10 cm long) and won’t feel great in a tank of small volume.

Water Parameters

There ought to be a stable biotic equalization in a tank. All molly fish are very thermophilic, and they lean toward water temperatures around 25-27°C.

If you ever need to change the water temperature of a molly, change it at a rate of 1 degrees Celsius per day so as to avoid any sort of stress or shock for mollies.

Following are the ideal water parameters for molly fish:

Temperature25-27 °C
Water hardness20-30 dGH
Ammonia0 ppm
Nitritre0 ppm
NitrateLess than 40 ppm

Molly fish can live in salt water, too and in a few cases, experienced aquarists even suggest putting some salt into the tank water purposefully. This won’t hurt the molly fish, yet it is important to bear in mind that most tank mates for molly fish would not be able to survive high levels of salt in the tank water.

In this manner, I’d prescribe to include some salt into the tank just if mollies live alone or when they are in isolation.

A water change of 25% should be conducted every week in a molly fish aquarium. This will help keep the water clean and healthy for the fish to live in. Otherwise, harmful chemicals would build up inside the tank, causing the death of molly fish.

The majority of the types of mollies that are economically available are easygoing fish and will do well in any quiet network tank. If there are any aggressive fish in the tank, the wide-bodied and latent mollies will be attacked or even killed.


With regards to filtration, mollies improve when the tank water is filtered thoroughly. They aren’t an untidy fish and like to live in a tank which has clean and regularly cycled water.

The best types of filters to use in a molly fish tank are:

  • Hold on back filter
  • Canister filter

One inquiry that surfaces regularly with mollies is “do mollies require salt in their water?” The response to this inquiry isn’t straightforward. Actually, the correct answer relies upon what types of molly you have.

Similarly, as with most fish, mollies do profit with some aquarium salt in the water, yet nothing has indisputably demonstrated that mollies should be kept in salty water.

The Salt-Water Myth for Mollies

My advice would be not to add salt in your aquarium as mollies are primarily freshwater fish.

Like any fish that has been over-reared (neons ring a bell), the hereditary line can once in a while be debilitated, and the fish turn out to be more vulnerable to sicknesses.

Numerous individuals at that point dishonestly ascribe the illness to an absence of salt, and a legend is conceived. I have kept mollies for near ten years now, and they have never been in a tank with any salt included.

Besides one minor infection episode a couple of years back (from an inappropriately isolated fish), they have dependably been sound and have had no issues rearing in substantial numbers. A large number of the mollies that I at present keep, are relatives of the first mollies.

Feeding Molly Fish

Mollies are omnivores in the wild and feed on little spineless creatures, green growth, and plant matter. In the home aquarium, they ought to be provided optimum nourishment and an assortment of vegetables.

Their most loved vegetables are:

  • Whitened zucchini emblems
  • Cucumber emblems
  • Shelled peas

If you don’t have time to cut and blanch vegetables, then a spirulina-based pellet can replace plant matter in their eating routine.

With the end goal to get them into rearing conditions, they should be fed live foods as a treat. Their most loved live-food are:

  • Bloodworms
  • Daphnia
  • Brackish water shrimp

Breeding Molly Fish

The molly fish is a live-bearer, which means that they give birth to live babies instead of laying eggs. Since it’s doesn’t disperse its eggs, there is typically a high survival rate among its fry (if the tank doesn’t have any vast predators).

Like most other live-bearers, reproducing mollies is extremely simple. It honestly comes down to:

fish + water = dozens of babies every month

Male to Female Ratio

Be that as it may, you must be cautious about what proportion of genders you keep in the aquarium.

In an aquarium that contains both male and female mollies, you should attempt to keep up a proportion of three females to each male.

Male mollies will persistently mate with any females in the tank, and If their consideration isn’t partitioned between a few females, the female they center around will get extremely stress from the continuous mating endeavors.

Molly fish reproduces every other month, provided that it has been provided with proper tank conditions. When mating the male fish utilizes its gonopodium which has a cylinder to discharge sperm.

Mollies are known to attain sexual maturity in 8 weeks.

Concerning the pregnancy signs they are:

  • Swollen belly
  • Dark gravid spot close to anal fin
  • At times, the pregnant molly acts stressed or lazy

Female fish may give birth to hundred babies without a moment’s delay. The number relies upon female fish’s age and size. Dark molly fish babies are brought into the world rather huge. They don’t get up from the tank base immediately and remain there or on the leaves of tank plants for some time.

Fry (babies) are incredibly delicate to tank water pollution that is the reason it’s prescribed to reestablish water in the tank with adolescents more frequently than for the most part.

Fry Care

To develop quickly, the babies need a broadened eating regimen. They are sustained with micro worms and processed high caliber fakes.

If those mollies are in a network tank, the ideal approach to guarantee a portion of their sear endure is to include some drifting plants or some thick plants like Java greenery.

The more plants that an aquarium has, the better chance there is of fry survival. Skimming plants are the best decision, as fry can without much of a stretch escape grown-up fish in the thick vegetation close to the surface.

Different Types

There are various kinds of mollies available; likewise, with other fish species, mollies have been hybridized numerous times.

In any case, two species are most essential in the aquarium world: sailfin mollies (Poecilia latipinna) and short-finned mollies (Poecilia sphenops). All different sorts begin from one of these two most usual sorts.

Both of these different species are genuinely easy to keep, but if you genuinely need them to flourish, you ought to learn and ace every one of the points below.

Water quality

Mollies are known for their versatility and solidness; be that as it may, you ought to take a stab at an ideal domain for their keeping. The easiest approach to do this is to recreate their original habitat by utilizing a perfect water temperature between 70-85⁰ Fahrenheit.

It is suggested to keep water temperature as steady as conceivable to maintain a strategic distance from unneeded worry for your fish.

This fish likewise lean toward hard water (15-30 dGH) and flourish at a higher water pH, ideally 8.0. The perfect pH shifts for various sorts of mollies, yet the range from 7.5 to 8.5 are always attractive.

It is realized mollies flourish in vigorously filtrated water, even though they are very equipped for adjusting to various conditions.

Although mollies aren’t messy, the general proposal is to change no less than 25% of the water on a week by week premise; make a point to change the water continuously with the end goal to keep the changing procedure less upsetting for your fish.

Tank Mates

Mollies are viewed as quiet fish. They live in gatherings, and many have had accomplishments in keeping them in network aquariums. In any case, others want to keep them in a solitary fish variety aquarium since they can end up aggressive toward other fish and between one another.

They are known to nip the fins of other fish frequently and the males are exceptionally forceful when kept alone without females to keep their consideration.

Health Issues

When lodging Mollies in an aquarium, you’ll need to watch out for the mineral substance of your water. If those parameters aren’t as they ought to be, your Mollies could succumb to various sicknesses.

The most eminent to consider is Molly Disease, also called Shimmies. However, Mollies can fall prey to various other freshwater fish illnesses as well.

Molly Disease is less of a genuine sickness and progressively an immediate consequence of a Molly living in poor tank conditions. In looking out for Molly Disease, you’ll need to watch your fish for torpidity, coated over eyes, or abnormally forceful conduct.

Furthermore, look for an irregular measure of shimmying in your fish. The ideal approach to treat Molly Disease is to clean your Mollies’ tank.

Notwithstanding Molly Disease, various freshwater fish infections could show up in your Molly, a large number of which happen because of the Molly living in an uncleaned or improper tank.

If your Molly starts to act differently, consider isolating the fish and checking its conduct in the cleaner water.

If your molly’s conduct doesn’t standardize, you might need to tweak the water parameters to see what’s bothering your fish.

Taking Care of Baby Mollies

A single female can give birth to up to 100 infant Mollies at once. When every one of the children is conceived, move the female into a secured segment of the first tank for it to rest and also keep the fish from eating its infants.

They do require a great deal of consideration as they are effortlessly inclined to sicknesses. The infant Mollies can be given daphnia, egg yolk, recently brought forth saline solution shrimp, or economically arranged infant livebearer nourishment.

After a period, you can utilize tropical chips or pellets to nourish them until they grow up. Live fish food like dark worms, grindal worms, and bloodworms help to support the raising of child Mollies.

In nature, the essential sustenance of Molly fish is green growth, so you could add some aquatic plants to the fry tank to give them a place to stowing away and additionally supply some vegetable nourishment.

Holding up until the point when the infants grow up (it’s frequently around two months until the point that they’ve multiplied in size), bring them into the network aquarium with the other bigger fish. Make sure to nourish the fish in the tank before applying the new Mollies to guarantee that they don’t think the newcomers are food you give them.

Top Food for Molly fish

Here is a list of the top molly fish foods.

Omega One Freshwater Flakes

This Molly food is perfect for most tropical freshwater fish that are omnivorous. They surely are extraordinary compared to other alternatives for Mollies. Omega One Freshwater Flakes are uniquely intended to meet the healthful needs of omnivorous fish simply like Mollies.

It contains a considerable measure of plant matter, which implies that it is brimming with nutrients and supplements, in addition to this, it has a decent measure of meat-based protein as well, which means that your Mollies will have their nourishing needs met beyond a shadow of a doubt.

Brackish Water Shrimp

These brackish water shrimp are exceedingly high in nutrients, supplements, and proteins as well. They are shrimp, so they are stuffed with proteins, yet they do likewise have different supplements that Mollies require.

With regards to great processing and a solid, safe framework, these saltwater shrimp unquestionably help. Additionally, they make for extremely delicious snacks for critical eaters.


To be reasonable, these krill are fundamentally the same as the saltwater shrimp we just took a gander at above. The major contrast is that it is another creature with an alternate look.

They are undoubtedly substantial, making them an extraordinary treat or infrequent supper supplement. While these krill do contain a lot of nutrients and minerals, about 60% of the aggregate is pure unrefined protein.


Mollies can be exacting eaters, and they get a kick out of the chance to have some assortment, so giving them some substantial bloodworms every so often makes for a fun tidbit and treat.

Much the same as with the krill and shrimp, these bloodworms have been solidified and dried, which implies that they are free of microorganisms, parasites, and absolutely alright for Molly utilization.

Bloodworms are brimming with protein, nutrients, and different minerals. Meanwhile, they don’t contain as many nutrients as plant matter, the measure of protein in these things is just surprising.


Daphnia is a tasty treat for your Mollies. Indeed, they are solidified and dried, so they are free or microscopic organisms and parasites that can be available in live food.

Daphnia is rich in protein, nutrients, minerals, and supplements, which are all required by your Mollies to fulfill them.

Related Questions

How long does a dark molly fish live for? By 4 months of age, dark mollies are completely developed. What’s more, dark mollies can live for 5 years in an aquarium. Mollies, for the most part, coexist with most other tropical fish and aren’t inclined to territorial behavior.

Can Molly fish live in a bowl? Never put ANY fish in a bowl as it does not provide enough space as well as water regulation to keep the fish in a sound environment where they can thrive.

Are Mollies aggressive fish? Mollies are once in a while aggressive towards other fish. They do incredible with any of the normal tropical fish and South American cichlids. Here are a few examples of tank mates for mollies: guppies, platies, angelfish, blood parrot cichlids, firemouth cichlids, gourami angle, dark convict cichlids, and tetras.


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