MOLLIES

 

Caring for Aquarium Molly Fish

 

Molly fish are some of the coolest aquarium fish on the planet. You don't need a huge aquarium to keep Mollies either. This site is a resource and community to keeping molly fish. Let's talk about the most important aspects to keeping mollies.

** It's very common for people to go over board with taking care of mollies because they are technically a "brackish" fish (which technically means they live in water that is mixed with salt). 

But remember, these fish have been bread in LARGE NUMBERS for years in normal water parameters containing no salt whatsoever. This means that these fish are so use to normal water.. that we don't need to worry about adding ANY salt to their water.

 

FOOD

 

Flake food can be used as a base, but should ideally be supplemented with meaty food. You can for instance give your Mollies grindal worms, blackworms, bloodworms and brine shrimp. Algae and vegetables should also be included in the diet.

 

What Size Aquarium Do I Need?

 

These fish like to swim around constantly and really utilize the aquarium space. A 20 gallon aquarium should be the bare minimum for a size on keeping these fish. I've seen lots of great 10 gallon tanks setup with mollies but ... I like to tell people a minimum of 20 gallons because these fish deserve that extra bit of space to move around in. 

** Keeping fish in smaller tanks like this is actually more work than larger tanks. The key is to setup that needed beneficial bacteria in your tank. Once you have that up and running.. the tank almost runs itself except for doing some water changes weekly. 

 

Community Aquariums & Fish Tanks

 

Mollies are popular in community aquariums, but you must keep an eye on them if you combine them with species that have long and flowing fins. Mollies are known to sometimes harass such species by nipping their fins. If you want to combine Mollies with species that have long and delicate fins, you should ideally choose specimens that are much bigger than the Mollies or aggressive enough to fend off a harassing Molly. Fin nipping might seem a minor problem, but the stress will have an adverse effect on the immune system of the harassed fish and the wounds can lead to lethal infections. 

Mollies are usually more interesting to watch when they are kept in groups, since they will display a much broader range of natural behaviors when kept together. They are not considered schooling fish. They form smaller groups with a very strict hierarchy, typically led by the male with biggest fins and the strongest coloration. Combining one male with several females and keeping only one male Molly in the aquarium is recommended. 

 

How Many Fish?

The old school rule of thumb known as "1 inch" of fish to each gallon of fish is always a safe rule of thumb to play off of. People hate hearing it because some fish are different than others, but it's just how the rules play out more or less. So if you add those numbers up to your molly fish, they should answer your question. Example, I have one 10 gallon tank and need to know how many Dalmatian mollies I can fit inside.

 An average molly fish sees an easy 2 inches of growth, so that puts me at around 4-5 fish in that tank. That is pushing the limits remember too. Just to be safe, I always undershoot this aquarium equation.

What is more important than actual 'swimming space' is water quality. This is why pet stores can have very healthy fish in tiny spaces. I always wondered why these resources preached to aquarium owners to have huge tanks but the pet stores can have tiny little tanks with lots of fish... It's because they are constantly doing water changes from a direct fresh water source. There is no better setup for clean water than to have a direct 'fresh' h20 supplement.

 

TYPES OF MOLLY FISH

 

 

 

• Marble Lyretail Molly

• Harlequin Sailfin Molly

• Golden Sailfin Molly

• Gold Dust Molly

• Gold Doubloon Molly

• Black Molly

• Balloon Molly

• Platinum Lyretail Molly

• Dalmation Molly

• Black Lyretail Molly

• Black Sailfin Molly

 

There are numerous types of molly fish but the most common type held in aquariums is known as the short finned mollies. For the most part, you can categorize them into two different groups of mollies. 

Most aquarium mollies are short finned because they are much easier to care for then Sailfin mollies. Sailfin desire a much more wide open tank with more water volume and harder regulated water temperatures. The image shown above to the right is known as a short finned dalmation molly. Very spectacular in color and shape. The fins on mollies are quite beautiful.

 

Roommates and Tankmates for Mollies?

 

Other Mollies, Guppies, Platys, Swordtails, Gourami fish, Female Bettas, Endlers, Danios, Minnows, Tetras, Snails, Shrimp and others. The Molly species of fish are very laid back and easy to get along with. It's usually not the molly you have to worry about, but instead the other fish that goes in for attack. Don't get me wrong, the molly does enjoy a good chasing and they are somewhat fast but they are going to do any harm. The most popular tankmate that I see housed with the molly are other livebearing fish species. They all somewhat act alike and do very well together. With lots of livebearers on your hands you will be constantly dealing with new fry being born on a weekly basis. These fish have babies all the time. 

A good rule of thumb to follow is to research each and every fish species you plan to roommate up with the molly. A trick I have learned through the years is to get into the Google search engine and do a search like this "molly fish with angelfish" or molly fish with betta fish." Its a very common thread for people to post questions as. Popular forums like AquariumGeek and Fishlore are great hangouts to get information on. You can even do a search around here on this network for involving tankmates with mollies (since we are devoted to mollies here!).

 

Molly Fish Breed All the Time!

 

After owning molly fish or any livebearer for some time, you will quickly find out how much they breed. Any molly fish can breed with another breed of molly. This makes for a crazy successful breeding platform. Any female can hookup with any male. Being livebearers, they do give 'live birth' to their babies. Females are usually always pregnant and thats how you can cosmetically tell the difference between males and females. That and fin differences.

The parents will feed on their newly born young and that makes for a nice snack. It's pretty disturbing but you get over it. If they didn't eat their own young.. there would be molly fish everywhere I think... It's not uncommon to see 1-3 babies swimming in your tank that somehow survived the birth and feeding of the newborns while you were at work all day. 

 

Behavior Traits of the Molly Fish

 

These guys are known to nip at other fish's fins but it's not to a drastic measure. They are for the most part very peaceful and to themselves. What I find very unique about Molly fish is the fact that they setup a division of hierarchy. Each Molly fish is going to have his or her level of importance and they live and die by these levels. I think of them as little soldiers that have different role ranks. People thought I was crazy for saying this until they actually realized it was happening right under their eyes. 

I'm not quite sure why they do this hierarchy of levels but it's just how the fish is. You will see a fish with less rank come up to a fish that has more power and it's almost as if the fish is kissing his shoes "sort of say." They will back out of each others way and do lots of unique things regarding their rank levels. I have had 0 incidents as far as the fish being over aggressive with other tank mates in the same habitat level. Very peaceful and civil to be around for other fish in the same habitat of living.

Quick Fact: Male Mollies are the Alpha Fish
You will quickly find out that the males are the king and most alpha when it comes to rank of the molly fish. They are the most beautiful as well. One male with three females is going to give your tank a very safe environment. This gives the male a chance to choose one out of a pack instead of forcing his way into what has to be done. Having numerous males in one tank will cause lots of aggression with Alphas fighting.

 

Pregnant Mollies and Breeding Molly Fish

 

If you think your molly fish might be pregnant, you are going to want to remove her from the other fish and put her in a nurser tank (separate tank). Make sure the habitat is the same as where the molly female originally came from is the same as the new tank. Give the female space and you will soon see if she will give LIVE BIRTH to her babies. No eggs.. Live babies.

If she does give birth to her live babies, make sure to remove her when she is done birthing. There is a chance she could eat her new young due to thinking they are a meal instead of her newly born young. Click here for more info on caring for new young.

Water Parameters for my Molly Fish?

The recommended temperature range for Mollies is 75-80° F since it is native to tropical parts of the world. The pH should be between 7 and 8, and using driftwood in the aquarium is therefore not recommended since driftwood is known to lower the pH value. Mollies will do best in a decorated aquarium where a big open area has been left from swimming around in.

Molly fish are said to be brackish water fish (freshwater mixed with saltwater) but the rate of saltwater should be very weak. Most molly fish that we buy as fishkeepers from pet stores are going to be most used to regular freshwater and that's what you should go with mostly. Salt in your freshwater does help out with bacteria and such but if you have other freshwater roommates.. it makes it hard to put salt in the water and mix up their water parameters juts to make the mollies a little happy. They will do just fine with plain freshwater and you can add small amounts but I personally wouldn't get too buck wild with adding salt.

Related Common Questions:

Use an Air Stone or Bubbler in my Tank?

The issue of an aquarium having too much oxygen is never a bad problem to have. If your fish don't have enough oxygen.. they are going to die very fast. Mollies and other livebearing fish do not mind the air bubbles in their tank and bubbler setups can really add value to your tank other than oxygen. If your thinking of setting up an air bubbler setup, maybe look into small sponge filter setups because they run from bubbler setups and really can filter your aquarium water very good while you also getting the added benefit of an air stone. You can really get two sides of benefit with one device on this one. The sponge filter setup is a very under-rated aquarium filtration method. A lot of breeders even today use sponge filters over all the leading technology in aquarium filtration. It's simple and hard to beat.

What Type of Decorations to Use?

Molly fish are considered to be "mid level" swimmers and really love all decorations. I'm not going to tell you that some decorations are better than others because it's not completely true. The only factor to keep into consideration is the fact of your fish being able to hide from bullies. In all aquarium circumstances there is going to be more aggressive fish along with more timid of fish. The timid fish will get pushed around and chased. It's important to have enough hiding spaces for those scarred fish to hide and feel safe in certain scenarios. The more plants your tank has, the safer it is going to be for aggression levels becoming dangerous. 

Can I use a 10 Gallon Tank?

It is very common for sources to tell you that you need a 20 gallon tank for these fish, but you can a bit smaller if you have a couple of mollies in the tank. For instance, a 10 gallon tank works for a lot of people and the fish are happy because they have a great home and don't live in small tiny pet store aquariums. These fish aren't going to squeeze into a tiny desk tank like some tetras and guppies do. It is advised that the species of molly fish that get larger in size then 3 inches be kept in a minimum of 30 gallon tanks. It's just a size thing of them taking up so much room in the actual aquarium.

The main reason why we preach that bigger aquariums are better is because they are easier to care for. The fish can pretty easily adapt to the smaller living space but the water quality is the factor that suffers. The more water you have in an enclosed area, the easier it is to be clean. Think of it like making 'kool-aid' in the kitchen. The larger container you have of water, the more diluted the mixture is going to be. This is compared to fish poop and uneaten food that sinks to the bottom of your aquarium. The smaller the body of water, the easier it gets dirty.