Aquarium Fish

Molly Fish - Mollies

The Molly is a tropical fish that prefers a little salt in their water. A teaspoon of aquarium salt per 5 gallons of water will go a long way in helping them. You may also see them in saltwater tanks from time to time. There is a local reef store here that keeps black molly fish in a regular saltwater tank with similar sized species. The molly is a very attractive tropical fish that comes in many different colors such as orange, green and black. Some of the more popular varieties include the sailfin, balloon and the dalmation.

The Molly fish is a livebearing tropical fish that can be fairly easy to breed. For many aquarists the biggest problem is not getting them to breed but stopping them from breeding. If left in a tank with other adult fish, the baby mollies will get eaten.

Mollies will eat flakes, frozen, freeze dried and definitely live foods.

Molly Fish Picture

Black Molly Fish

Molly Giving Birth Video

Mollies, Molly Fish Care Facts

Scientific Name : Poecilia sphenops

Common Names : Lots of different types are available: Black Molly, Lyretail, Sailfin, Liberty, Mollie, Pointed Mouth, Short Finned, Mexican, Golden, Piebald, Ghost Pearl, Gold Dust, Red Sunset, Dalmation, Ballon, etc.

Care Level : Easy, very good for freshwater beginners if keeping a single sex. Keeping both sexes could cause problems since this fish is such a prolific breeder.

Size : 2 to 4 inches (5 - 10 cm) depending on the species

pH : 7.5 - 8.5

Temperature : 70°F - 82°F (21°C - 28°C)

Water Hardness : 10° to 25° dH

Origin / Habitat : Central America

Life Span : 3 - 5 years

Molly Fish Temperament / Behavior : Peaceful

Molly Fish Breeding : These are livebearers so it is fairly easy. Adding a little aquarium salt will help. Do you have a pregnant molly fish? Read the breeding guppies article for more information. That article talks about guppies and swordtails, but the process is very similar for the Molly fish babies.

Aquarium Size : 20 gallon minium, prefer tall aquariums

Molly Tank Mates : Not many - some feel they should only be kept with others of the same species.

Fish Disease : Freshwater Fish Disease - Diagnose, Symptoms and Treatment

Diet / Foods : Give them a varied diet consisting primarily of flake foods but supplement with live and freeze dried foods occasionaly.

Tank Region : All over the tank.

Gender : Males are more slender, females more round. Males also have a modified anal fin.

Author : Mike FishLore

Molly Fish Tips

From: Sharon via email
How often does the Molly breed and can you stop them if you want to?
Assuming that you have pairs, they will give birth every 30 days if the tank conditions are right. One sure way to stop them is to remove the males or females and only keep one sex in your tank. Also, keep in mind that mollies, like some other livebearers (i.e. the Guppy, etc.), may remain fertile for about 3 months after getting pregnant and separating them from the males.

From: Albret
I moved my female today to a breeding tank, I think she might have been too stressed and aborted the pregnancy. How can I tell if she did?
Moving too soon to the drop may cause your livebearer to abort the process because of the stress involved. Leave the female where she is and if she does not have any babies in the next week or so you can assume that she aborted the pregnancy. Try to keep them in the same water. Moving to a different tank with different water parameters (temperature, pH, etc.) will cause stress. A breeder net or a breeder box or floating plants will allow the babies to hide from the larger fish in the tank.

From: Chris
Mine had about 39 babies and as they grew I couldn't tell the sex of them. I knew the females where more round but does the male have a larger top fin?
You should also be able to tell the difference by looking at the anal fin. It is usually much smaller and more elongated on males.

From: Lisa
On average how many eggs do females lay in one pregancy?
Mollies are livebearers which means that they don't lay eggs. The fish are born swimming. The number of fry depends on the size, age and health of the fish. Generally speaking, they can release anywhere from 2 - 60 babies or more.

From: Sophie W.
How long do they live for?
If kept in good water conditions they generally have a lifespan of 3 - 5 years or more.

From: Haley
How long does the pregnancy last until the babies are born?
The gestation period for this livebearer usually takes about 4 weeks, sometimes slightly longer.

From: Nita
My molly had babies and we put them in a separate tank with the mother and she ate her babies. Is this normal behaviour of females?
Unfortunately, it is common for them to eat their young. Next time just place the babies in the separate tank or get a breeding net for the fry.

From: Leah
I've been breeding Mollies, Swordtails, and Guppies since I was about 12. I've tried breeding betta fish, but the babies are so small and fragile that they always die. I took a long break from livebearers and had some tetras and angelfish. I had a Dalmation Molly that had 14 babies and only one made it to this day. The mom and dad got eaten and I moved the baby one to its own tank immediately. I just bought him an all black girl and she just had 9 babies two days ago! Black babies are the absolute cutest! The 2 adults never picked on them but I moved the parents to a larger tank and bought 2 gold dust mollies and a male swordtail. Breeding this fish is the coolest thing in the world. They are so adorable and is a hobby of mine.

From: L. Fish
Yesterday we bought a white molly, black molly and two spotted ones. We woke up this morning and our white molly was dead and now there are about 15 to 20 babies! We had no idea this was going to happen it was a shock to say the least. The other mollys haven't been interested in eating the babies, but we will see.
Most likely they will get eaten by the other fish in the tank. Mollies are similar to other livebearers in that they are prolific breeders. If you have mixed sexes in the same tank, your water parameters are decent and they are being fed adequately, you'll soon have babies.

More Molly Fish Tips

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