An In-Depth Look At Molly Fish
I used to be a big fan of goldfish, I wanted nothing but goldfish, fancy tailed goldfish to be precise, but now... Well, now it is all about Molly fish. Poecilia Sphenops (Short-Finned Molly) is my favourite and the kind that I keep now. Right now, I have Bait and Tackle and seven fry that one of them dropped in my tank on Day three of my new aquarium. They are Lyretail short-finned Dalmatian Mollies and watching them has driven me to learn everything I can about them and what they need to be happy, healthy and to breed. This post is to share my love of mollies with you and maybe some helpful information for anyone looking to bring some of these fish home.
1. The Molly
3. Water requirements
8. About Me and My Fishes
Molly fish are often quoted as an easy going beginner fish and are usually quite cheap to buy at the local fish store (LFS). They are usually said to be great community fish, peaceful and small and perfect for people just starting the hobby. While some of this is true, Mollies have a bit more complexity to them than that. Mollies are livebearers, meaning instead of laying eggs they “drop” baby fish called fry. They are a muddled species and it is often hard to tell exactly what kind of fish you have. They are members of the genus Poecilia. Mollies had previously been placed in their own genus, Mollienesia, and it was from this that the common name ‘molly’ was derived. The name Mollienesia was coined in honour of FranÃ§ois Nicolas Mollien, a French politician of the late eighteen and early nineteenth centuries. Practically all the mollies sold to aquarists are hybrids of a number of species found across Central America and the southern United States. They are often said to be brackish fish, however in the wild they exist in both completely freshwater areas as well as almost full seawater. They spend much of their time foraging for food among the various plants and most of their diet consists of algae and other forms of plant life. While they are omnivores (eating both meat and plants) their diet in the wild is only supplemented by live foods.
Mollies are a hard fish to place. There are several muddled varieties and colourings to confuse you. I probably will miss a few and I won’t be able to provide pictures of them all (I’d need a book to do that), so I will just include some of the more popular types and something about them to get you started. There are 32 known species of Molly that I could find. However, most Mollies that you get from the LFS are hybrids so it is difficult to determine just what type you have. They can come in many different colours such as black, marbled, gold, red, white, green and in the case of the Liberty Molly, red, white and blue. Mollies can come with many different fin types as well, such as the common fin, the lyretail, and the sailfin. Some of the popular ones are as follows:
Dalmatian Short Fin Molly
Poecilia Sphenops (Short-finned or Common Molly):
Size: Males approx 3 inches, Females can get up to 4 inches
Temperature: 77-82 degrees
Lifespan: 3-5 years
Male and Female Sailfin Mollies
Poecilia Latipinna (Sailfin Molly):
Size 4-6 inches
Temperature: 75-80 degrees
Lifespan: Short, 1-3 years. Males can die one year after reaching sexual maturity
Poecilia Velifera (Yucatan Molly): Though remarkably close to the Sailfin Molly this fish is a class of it’s own. This fish is hard to find in shops as it is often not a true form but a hybrid or, even worse, a Sailfin Molly in disguise.
Size: 3-4 Inches
Temperature: 77-80 degrees
Lifespan: Can live up to 5 years
Balloon Belly Molly
A balloon molly and male sailfin molly by guppy man
Balloon Belly Molly: Though not a species of it’s own, and although I dislike them personally, I suppose I should include the Balloon Belly Molly. This fish can be created from any of the above species with varying colours, but it always has the distinctive round belly and curved spine that is creating by purposely breeding deformed fish. This fish is a complete hybrid and is manmade. It has a much shorter lifespan and it’s immune system is weakened so it gets sick much easier.
Size: 3 inches to 5 inches
Temperature: 75-82 degrees
Life Span: Up to 5 years, if you are lucky
Poecilia Chica (Dwarf molly): Hard to find miniature fish.
Size: 1 - 2 inches
Temperature: 75-79 degrees
The distinctive red, white and blue of the Liberty Molly
Poecilia Salvatoris (The elusive Liberty Molly):
Size: Up to 5 inches
Temperature: 71-80 degrees
Lifespan: 5 years
There are many other types of Molly especially wild species that are out there. A good reference to see all the different types is http://en.wikipedia.org/wiki/Molly_%28fish%29.
A petenensis on the right and mexicana campeche on the left, image by Snowman
Mollies can be said to be hardy fish, but that all depends on the type of Molly you get. For instance, the Balloon Belly Molly is prone to disease and swim bladder issues due to its deformed frame. Hardy fish or not, they still need certain water parameters to do well. The long argument with mollies is: Freshwater or Brackish.. that is, to add salt or to not add salt. In the wild Mollies can live in near seawater or pure freshwater. The choice really is up to you. HOWEVER, bear in mind, mollies like HARD (15-30 dH) water with a high Ph, preferably close to 8.0. Adding salt to your aquarium if you have a low Ph or soft water can make the environment much more suitable to Mollies. Mollies like to munch on algae so having some in your tank is actually a good thing. Mollies are extra sensitive to Nitrites and Nitrates so it is best to keep these as low as possible (Nitrites at zero and Nitrates below 20 ppm). Doing extra water changes of 20-30 % is recommended. They like a temperature of 75-85 degrees. Mollies are best kept in larger aquariums and a minimum size recommend is 20 gallons.
Mollies are said to be a good community fish. This is not as easy as it sounds. As Mollies age, they can get to be a bit aggressive and tend to get nippy (Biting on the fins of other fish). Some Mollies have been known to “pick” at other fish, especially goldfish, and remove some of the slime coat that protects the other fish. Mollies are a tropical fish, they cannot be placed with cold water species and should never be put with a fish that is smaller than them, like neon tetras as they will chase them down and eat them if they can. Mollies like to live in groups, so one male to three or four females is the best situation for them. If you don’t want fry (good luck with that) keeping all females is okay. Never keep all males together as they will fight and nip fins. Mollies will eat the fry of their own and other fish so baby fishes should be removed from the tank if you don’t want to lose them. Mollies have been known to eat small snails. If you place salt in the aquarium, only place salt tolerant species with them. Although Mollies are said to be a good peaceful community fish, males of the species will harass other fish if not given enough females to give their attentions too. Also, male Mollies will bother other males in the tank if there are too many. As a personal choice, I prefer to keep Mollies in a single species tank, but others will gladly tell you of their success with them in a community tank.
Mollies are Livebearers. What this means is that instead of laying eggs, they give birth to live, swimming fry. Mollies breed like rabbits! It is best to keep one male to three or four females or the male will stress out the female trying to copulate. Male and female Mollies are really easy to tell apart. The female’s anal fin is shaped like a fan, while the male’s anal fin is shaped like a stick, straight and thick. (This is called the Gonopodium, and he uses this to hook onto the female and insert *****.) All Mollies will look like females until they reach sexual maturity at about 8 weeks. They are fully grown at 3-4 months.Male and Female Mollies
Mollies are prone to abort births when stressed, so it is best not to move the female too close to the drop date. If you are not sure, then its best to leave them where they are and move the fry after the birth. You can try providing the fry with lots of bushy plants to hide in. Floating plants, like Hornwort, work best, but plants like Java Fern can also be good. Remember to cover the intake tube of your filter as little fry can get sucked up into it. The gestation period for mollies is 21 to 30 days and they can get pregnant again in a few hours. Female Mollies can “store” ***** and get pregnant again up to three times within six months even without a male fish present. Mollies are almost always pregnant. Mollies can give birth to as few as 5 fry or as many as 100 (sometimes even more!). The first batch will almost always be small however. A female Molly will begin to get a very round belly when she is pregnant and when she is ready to drop her fry she takes on a squarish shape. Also, on some Molly fish, you can see a dark patch by the back of her anal fin. This is called the gravid spot. It is harder to see on some Mollies than on others.
Mollie fry are ready to begin eating as soon as they are born. Live plants or algae are really good things to have so they can feed right away. You can grind up adult flakes (into a powder) and feed them this or buy specially made fry food for them. They also do well with live or frozen (THAW FIRST) baby brine shrimp. Some people have had success with cooked egg yolk mixed with some water and made into a paste. My fry wouldn’t eat it.
The fry are ready to be put back in the main tank (if you moved them) when they can no longer fit in the mouths of the adult fish in the tank. Mollies like a warmer temperature to breed in so keeping the tank up at 80-82 degrees really helps them along. Remember, Mollies and their fry are sensitive to water parameters so keep the Nitrite and Nitrate low. Many people have reported that Mollies like to give birth at night.
Mollies are technically omnivores. HOWEVER, in the wild they mostly eat algae and plant life so they could also be called herbivores. Feed them lots of greens. A flake food for herbivores is good as are algae wafers. Mollies will eat live foods like bloodworms and brine shrimp, as well as the fry of other fish. You can feed Mollies a bit of boiled, de-shelled pea as it is said to help fix constipation from a protein rich diet. I feed my Mollies twice a day, a tropical fish flake food in the morning and an herbivore fish flake food at night.
BE WARNED! Mollies are beggars! They are said to be swimming stomachs and will try to eat you out of house and home. Do not overfeed these fish. They like to munch on algae so it may be a good idea to let some grow in your tank for them. Feed no more than what the fish can eat in three minutes. Also, it is best if you feed fry up to five times a day. Small meals. I feed mine three times a day and an algae wafer they can pick up all day long.
I did a lot of research and asked a lot of questions to get the information in this post and opinions vary widely on these fish. If you would like to know more or disagree with the information here are some links to sites I used over the course of my studies on these great fish!
<phttp://www.wetwebmedia.com/fwsubwebindex/mollies.htm - This site is VERY helpful as it posts FAQs about mollies asked by people like you.
Edit: All pictures beside the one for Poecilia Sphenops were found on the internet. They were used in a non profit, non personal gain way for information purposes only and can be removed if the owner wishes.
Hi, I am Wythori and I just recently got back into fish keeping. I was going to get a goldfish, but when I told the store I had a 10 gallon (I actually have a 20 gallon) they told me goldfish get too big and showed me the tropical fish section. I was going to get platies, but when I looked down and saw the Lyretail Dalmatian Mollies I fell in love. I immediately bought two, never knowing anything about the Nitrogen Cycle or how to care for them, or anything about Mollies at all. They were just pretty fish.
I came to this site and learned pretty quick that I went about getting fish the wrong way. So, I am, as of today, on Day 13 of a fish-in-cycle and am hoping my fish survive the hardship of this process. On Day 3, one of my Molllies gave birth to 5 fry. I was flabbergasted... I didn’t know how to take care of baby fish! So, I read a lot, asked a lot of questions and now, on Day 13, they are slightly bigger, well fed and now there are 7 of them.
My two fish quickly wormed their way into my heart by their silly antics. Bait, the white one with black spots (See picture for Poecilia Sphenops), is not the least bit shy and always comes to the glass to greet me whenever I walk by. Tackle, the black one with the white spots (Again see above picture), likes to swim circles around a leafy plastic plant that I have and take the air bubble express to the top of the tank (He swims through the aerator!). She must have taught this trick to Bait because they both do it now.
Whenever I do a partial water change (Daily right now) they are very curious and will be right there giving me fishy kisses. I have to be very careful not to siphon them up with the water! The fry are in a breeder net (To keep them from becoming snacks) and they are also very unafraid of my hand. When I clean out their net, they are all there smacking my hand to see what I taste like. I have taken more pictures of my fish than I have of anything or anyone else (besides my fiance). I know there are many other types of fish in the sea, but I fell in love with the Molly fish and I see a long future of my taking care of them.
I hope this post helps you and encourages you to take another, closer, look at these wonderful fish.