All You Need To Know About – Molly Fish Care!

Molly Fish
Written by Dennis

Little MolliesMolly fish care procedures are extremely easy, which is the reason why every aquarium owner has at least once in their lifetime kept molly as a pet. This fish has a beautiful skin and vibrant color that makes it the worthy companion of every ornamental fish tanks.

Often people mistakenly think that these fishes have only one single species but the real fact is that they belong to 3 different species. However, the hybridization has made it difficult to identify which fish has come from which two.

Caring is very simple for these little beauties, though the hybrid fishes are less sturdy than the real ones so make sure you follow certain measures as it is impossible to distinguish the real one from the hybrids.

Behavior of Mollie Fish:

They belong from the Poecilia genus and very calm in nature. The most serene feeling in the world will be when you see one of them swimming gently. They easily get stressed if any outer force is given to the aquarium like the hitting on the glass of the tank through the tip of the finger.

It is not recommended to keep them with mean fishes like barbs, they are the devil in nature and will disturb these slow swimmers.

The best way to keep them active and happy is to keep them in groups. They love to stay with their other partners and often behave awkwardly if kept alone.

Popular Breeds Of  Mollies:

Selective breeding of this genus Poecilia has resulted in several varieties and molly fish colors. Some of the popular varieties are-

  • Black Mollies: Starting from Venezuela in the north to the Mexico in the south these fishes are found everywhere. They are also native to the both South and North America. Mostly these are the freshwater fishes but sometimes hobbyists mistakenly treat them as the brackish water fish.
  • Gold Mollies: These fishes are nicknamed as the 24 karate because of their golden glow and widely found in aquariums.
  • Green Mollies: These fishes are also nicknames as Sailfin which are the hybrid of Poecilia Latipinna and P. velifera.
  • Pot Belly Mollies: The deformed spines caused by a genetic defect in these fishes give them the pot belly look. These fishes have a bad reputation of a short


You can keep a Mollie in any housing as they are less demanding, but to let them thrive healthily it is the duty of every aquarium enthusiast to give them a comfortable fish tank.

To do that you need to buy a fish tank that can hold at least 10 gallons of water. Make the bed with gravels and rocks. Also keep it shallow. Use a good quality filter as filtering the water every now and then is a crucial part of keeping these fishes healthy and active.


The temperature of the water should be 72 to 82 degrees F, as it is the ideal temperature when these fishes are in their happy mood. Keeping your fish happy and playful is mandatory for breeding.

pH Level: The water should be moderately hard to very hard and pH level must be kept in 6.5 – 8.

Filtration: Filtering your tank appropriately is very crucial for the health of these fishes. I will recommend you Fluval 106 Canister Filter or higher if you have bigger tank.

Molly fish aquarium should be large enough from the start as more water give them a stable environment which is highly beneficial to them. Other than that the sailfin breed grows larger in size so if you have a school of them then keeping them in a 20-gallon aquarium will be appropriate.

Sudden water quality fluctuation is bad for the fishes which is why after cleaning the aquarium do not forget to mix at least 50% of the old water so that the fishes can have enough opportunity to  get acclimatized with the new environment.

Though the real fishes are sturdy in nature the hybrid ones are little weak which is why a proper care of them is essential. To keep them safe from diseases, clean your aquarium at least twice in a month and add marine salt as prescribed in the label.

Mollies were generally saltwater fish bread to live in freshwater but 100 percent freshwater will make them sick (Fin Rot starts pretty quick), they live happily in freshwater added with small amount of marine salt, which is also known as brackish water.

Fish Food For Mollies:

These fishes are omnivorous in the wild and love to eat whatever you feed them.

If you are confused about what to feed your Poecilia then let me tell you that anything you eat can be its food. You can feed them raw vegetables like zucchini medallions, shelled peas, and cucumber medallions. But do not forget to cut them in small pieces as hard foods are not for them.

To give them the proper diet you can feed them a high quality flake food or you can also feed them live, frozen and cooked foods.

Live foods include insects, blackworm, bloodworm, brine shrimp and daphnia. In case you are feeding frozen foods, make sure you thawed them properly before feeding.

Molly Fish Breeding Tips:

Though mollies fish can make your day by their calm and serene look but among them, some can be really naughty.

If you see a particular fish chasing another fish and becoming a real pain, brace yourself as it’s the time for mating and after a couple of days, may be you are going to get some cute fries.

However, the matter is not easy for everyone as it looks like because the primary complains of many aquarium hobbyists regarding these fishes is that they are not reproducing.

This can happen for many reasons including your tank does not have enough female or the males are not interested in the females, whatever the reason may be to get some baby fries your need to breed them.

How To Breed?

Unlike other fishes, I have mentioned in my blog, these fishes are live-bearers, which is why breeding them is not at all difficult. A proper environment and technique will help molly fish giving birth to her fries.

First start with identifying the male and female fishes. You can easily do that by the fat and round body of the female fish and the males are comparatively thinner.

After that comes the correct ration in which you need to keep your fishes so that mating occurs.

Molly Fish Male Female Ratio: Make sure your aquarium has fishes according to the ratio of 3:1 where the females will be thrice than the males. While mating them, do not keep other fishes in the tank as it will help the male to concentrate on the females.

Molly Fish Fry Care:

While mating you may see that the male continuously chasing the female, almost every 5 minutes. It may even result in stress or death of the female. So after considerable time separate the male from the tank to another one.

Also if you see that your female is carrying babies and ready to give birth then it is preferable to separate the pregnant female from the fish tank as the males may eat the fries. Usually, the gestation period of molly fish is 4 weeks.

You can also use a fry trap which you can avail online here easily or buy a small nursery aquarium like these. Cleaning the trap is essential so use warm water to wash it as it will ensure better health of the fries.

In the trap, place the mother in the upper portion where there will be a crack for the fries to fall down. As the molly fish giving birth completed, take her out from the trap or you can keep it her there for some moment if you feel she is stressed out.

Molly Fish Babies Food:

Feeding the babies properly is very crucial for the adequate growth of the fries. You can ground the high quality flake food and feed them, or you can make small pieces of vegetables in order to feed them.

Live foods are also a part of their balance diet, so feeding small pieces of them is essential. After the fries are mature enough to face their parents you can return them into the original tank.


What is the lifespan of molly fish?

  • If your fish is a pure one, then the lifespan expectancy is 3 – 5 years. For the hybrid fishes, the lifespan can be short.

Is my molly fish sick? How to identify that?

  • Check for lumps in the body, discoloration, and irregular swimming. Make sure the lump is not for pregnancy. If discoloration takes place, then your fish is definitely sick. It is advised to quarantine it immediately. This is an integral part for the caring of molly fish

How long are molly fish pregnant for?

  • The approximate time is 4 weeks though it differs.

What is the recommended water temperature for molly fish?

  • 72 – 82 degrees F

How difficult is molly fish care?

  • Easy


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