Last updated at 4/15/2024
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Even after years of experience, I acknowledge that raising molly fry can be difficult. That is especially true for those who are new to fishkeeping, as molly fry come with many questions.
So, after quite some time, I decided to gather some of the most common questions into one thorough article. In many cases, I will link to another article I wrote so that you get the picture in detail.
Ultimately, in the second part of this article, I will list some essential tips that will help you care for your molly fry and keep a large portion of them alive.
For those of you who are in a rush, here is a table that gathers some of the most crucial information on molly fry:
| Feeding frequency | Five times a day |
| Separation duration | Two months |
| Survival rate | ~50% |
| Tank size | 10-20 gallons |
| pH | 7.5-8.5 |
| Temperature | 75°-80°F (24°-26.7°C) |
| General hardness | 12-25 dGH (200-416 ppm) |
| Carbonate hardness | 10-25 dKH (178-450 ppm) |
| Ammonia | 0 ppm |
| Nitrite | 0 ppm |
| Nitrate | <20 ppm |
A transparent molly fry, digesting its meal.
These are the courses you can take with molly fish fry:
Dealing with molly fry for the first time can be overwhelming, especially if they catch you by surprise. In the second part of this article, I will show you how to raise them properly (assuming you go with the first option).
But you don’t have to keep the fry if you don’t want to. Leaving them in the main tank can be pretty nutritious to the rest of the fish you own. Many fish owners go with that route.
You can also get rid of them by trading or selling them. You may be surprised to find out how many fish stores show great interest in those little creatures.
This molly fry found shelter behind driftwood.
Sounds interesting? Check out this article where I discussed what to do with molly fry. I distinguished the steps you can take with wanted fry from those of unwanted fry and elaborated on each.
Molly fish typically deliver between 40 and 100 live fry in a single session, but that isn’t always the case. Some mollies will produce less fry because they haven’t fully matured yet or are highly stressed.
If you suspect that your molly fish is pregnant, there is a high chance she will deliver a lot of fry in a single batch. However, many factors can prevent this from happening.
For example, if the temperature consistently fluctuates, the female will be stressed and possibly absorb some of the fry. Also, some mollies are just too old or young to deliver so many fry.
Still curious? Click here for more information on how many fry can a molly fish have. I also discussed how often molly fish deliver and how you can ensure that the fish gives birth without complications.
About fifty percent of the molly fry eventually survive and reach adulthood, but you can improve the survival rate by taking a few steps. That includes adjusting the water parameters and the feeding routine.
As previously discussed, mollies can deliver up to 100 fry in a single batch. But that doesn’t mean all of them will survive. In a typical tank, about half of the fry will die.
You can improve this number by raising the fry in a dedicated nursery. If you can’t do that, ensure there are plenty of hiding places in the community tank.
You should also feed the fry properly. Just remember that their feeding schedules and food types are slightly different from adults.
As I’ll explain later, molly fry can eat whatever adult mollies eat, but you have to grind the food into tiny pieces. They also eat more frequently than adults (up to five times a day).
Caught your attention? Here you can find more information on the molly fry survival rate. You will find a step-by-step guide to improve this number and bring it to the maximum.
This table summarizes what molly fish fry eat, depending on their age:
| The Food Type | At What Age |
| Infusoria | Until day 7 |
| Baby brine shrimp | Between days 7 and 21 |
| Freeze-dried/frozen foods | Day 21 and beyond |
| Worms | From week 5 and beyond |
| Flakes/pellets | From week 8 and beyond |
As you can see, molly fry eat different kinds of food, depending on their growth stage. Start with infusoria up to week one. This is highly nutritious, microscopic food that fish fry love.
Then, you can move on to larger types of food, such as baby brine shrimp, freeze-dried food, worms, pellets, flakes, etc.
While it is highly recommended, you don’t have to change the fry’s diet at different stages. You can stick with one type of food, although I suggest mixing at least two. Just make sure it is small enough to fit in their mouths.
Until one month, you should feed the fry about five times daily. Give them the amount they can finish within two to three minutes.
During their juvenile stage (days 30-60), you can cut the meals to 3-4 times daily. After two months, the fish reach their fingerling stage and can be fed twice daily.
A few days old molly fish fry, eating algae grew on a plant.
Wish to learn more? Check out my complete molly fry feeding guide. In there, I take you step-by-step through the process of feeding these delicate creatures. I also included some excellent videos for a better visual understanding.
These are the general molly fry growth stages:
Up until day 30, the baby mollies are considered fry. You won’t be able to spot any colors or tell if a fish is a male or a female.
During that stage, they are incredibly vulnerable. Most of those who won’t reach adulthood will die during the fry stage (about fifty percent).
After thirty days, you should recognize the breeding organs. You may see the males’ gonopodium and the females’ gravid spot (representing the womb).
After two months, during the fingerling stage, the mollies are about 4 to 6 inches long and ready to reproduce. If you wish to avoid that, you should separate the males from the females at this point.
Sounds interesting? Feel free to visit the article where I discussed the molly fry growth stages. Besides detailed pictures, I included a fascinating video that follows the fry’s growth until day 32.
Molly fry start developing colors during their first month. However, these will probably change and become more intense as the fish grow. At four months of age, the young molly will achieve its final appearance.
While it can take a few months for the fry to develop colors, you can take a few steps to accelerate this process. The key is to keep the fry healthy.
You can do that by maintaining a relatively warm environment (about 80 degrees F) and feeding the fry adequately.
Still curious? Check out this article where I discussed when molly fry get their colors. I made sure to list all the steps you should take to achieve the most beautiful and colorful molly fish.
Here is a table that shows what equipment molly fry typically require:
| Equipment | How Necessary? |
| Filter | Very |
| Heater | Very |
| Air stone | Somewhat |
| Lights | Somewhat |
| Air pump | Not necessary |
If you grow your molly fry in a nursery, you must equip it with the same devices you would offer adult fish. That includes a functioning filter and heater. These two are the most crucial.
Then, you can add an airstone and lights. The airstone isn’t mandatory, although it becomes useful if the tank holds a few dozens of fry.
A lightning system is also beneficial because it helps you create a day/night cycle. Aim for 10 to 12 hours of lights, and don’t forget to turn them off during the night.
Caught your attention? Click here for more information on what equipment molly fry need. I made sure to include the particular gear I use when growing a new batch of fish fry.
Molly fry rarely survive in community tanks. Ideally, they should be raised in a nursery for about two months. Afterward, they will enter their fingerling stage and be too large to fit in adult fish’s mouths.
Keeping the molly fry in your main tank isn’t ideal. They will be chased down and eaten by adult fish. If you must do that, ensure you place a sufficient number of hiding places.
You can use decorations, plants, etc. If you have the time, investing in floating plants with brushy roots is excellent. Fry love getting behind those. These are the ones I recommend:
Three days old molly fry, swimming at the top of the tank.
Wish to learn more? Click here for more information on whether molly fry can survive in the main tank. If you can’t start a nursery, you will find everything you need to raise them in your community tank.
Here is a table of a few common freshwater fish and their relationship with molly fry:
| Fish Type | Will They Eat Molly Fry? |
| Mollies | Yes |
| Angelfish | Yes |
| Bettas | Yes |
| Guppies | Yes |
| Neon Tetras | Probably |
| Dwarf Gouramis | Probably |
| Rainbowfish | Probably |
| Bottom Dwellers | No |
If you raise your molly fry in the main tank, remember that some fish are more aggressive than others and may chase them down.
Adult mollies, angelfish, bettas, and guppies won’t hesitate to ear the fry. If you own those, don’t introduce the fry until two months of age.
Neon tetras, dwarf gouramis, and rainbowfish are less dangerous but should also be avoided if possible.
Bottom dwellers like cory catfish aren’t a danger to molly fry at all, and they can happily share the same tank. If some of the fry go missing, they probably died for other reasons.
As a rule of thumb, any mid and top dwellers that can fit the fry in their mouths are a danger to molly fry. Introducing dense foliage with those types of fish is crucial.
Sounds interesting? Check out this article where I explained what fish would eat molly fry. I also listed a few tips that may help you raise the fry with adult fish.
These are the general steps you should take to keep molly fry alive:
Following those steps will increase the survival rate of your molly fry drastically. They are great if you are in a hurry and wish to keep the fry alive. However, in the second part of this article, I will show you how to care for the fry more thoroughly.
This two-week-old molly fry started to develop some colors.
Still curious? Check out this article where I explained how to keep molly fry alive. In there, I elaborate on each step that I mentioned earlier.
Adult mollies produce live babies. When the fry arrive, you can either raise them or donate the creatures. If you’re hellbent on raising the baby mollies, you will most likely follow these steps:
Even though molly fry are small, you cannot keep them in a bowl. They need more space. Otherwise, the stress will kill them. But what is the appropriate size of a nursery tank?
Many newcomers are convinced that the biggest tanks are the best. That idea has been propagated by some professional aquarists who keep encouraging beginners to buy the biggest tanks they can find.
In a way, this advice is not wrong. There’s no such thing as a tank that is too large for adult mollies. But baby fish are different. They don’t have the same strength as their adult counterparts.
As such, you cannot expect them to cross large distances to find food. The exhaustion will probably kill them. Some babies will starve because they cannot find the food you added.
