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.
1. Bacteria & Filtration
2. Tropical Temperatures
3. High Quality Food
4. Good Tank Mates?
5. Water Changer 🙂
7. Timer for Lighting
Types of Mollies
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.
- 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
Behavior Traits of Mollies
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.
Mollies 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 with babies and that’s 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.
Water Parameters Needed
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.
Common Questions Asked:
Use an Air Stone or Bubbler?
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 pump 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?
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.
Do I need an Air Pump?
If you have a filter running on your tank you don’t necessarily need an air pump but it’s a good backup in case your filter fails. We always advise people to buy an air pump and throw on a sponge filter instead of an air stone. They do the same thing except they filter your water TOO! It’s knocking out two birds with one stone “sort of say”.. And again, if your filter fails that sponge filter will probably save the tank by itself.
How Many Fish in Tank?
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.