When To Separate Baby Molly Fish? Find Here!

Mollies live in a variety of habitats, including brackish, saltwater, and freshwaters around the world. Depending on species (male or female), they can grow anywhere from four inches to six inches long, depending on species (male or female). Therefore, owners should research what kind of Molly fish they have before deciding when to separate them. Usually, the death of fry is a common problem in a community tank. Hence, it is best to separate baby Molly fish. But do you know when??

You should separate the baby Molly fish after they reach six months of age or earlier if there are signs of aggression at a smaller size. However, some may say that even younger than that will do just fine as well. The decision is ultimately up to the owner and how they can handle their fish.

The first thing you should know about Molly fish is that they can grow up to 4 inches in length. These little guys are not just cute, but they take up a lot of space too. So if you’re thinking about separating them then, make sure the tank is big enough.

Read on for some other important tips and tricks for separating Molly fry from the main tank.

Do You Need To Separate Baby Molly Fish?

Molly fish are extraordinary pets, and they are widespread for beginner aquarium owners. These little guys grow to be about four inches long and can live up to three to five years in captivity if properly cared for them.

Molly Fish thrive with other mollies the same size as them. However, it’s not uncommon for them to fight a lot during their earlier stages. So it might be necessary to separate your baby mollies into different tanks until you know that everyone is big enough. These molly babies look so adorable that you won’t take a chance to loose them.

Baby Mollies need at least 1.2 gallons of tank per one adult male or female. Of course, the more room there is, the happier and healthier they will get.

The issue with keeping baby mollies together is that their bodies are tiny and are more likely to stick in the filtres or heater. Also, since these fish are smaller with vibrant colors,  larger fish can attack and eat them.

Fin nipping between adults and babies is a severe problem in Mollies. It might look like the Mollies are playing, but it could also lead to some severe injuries which you wouldn’t want to see in your aquarium. Therefore, it is necessary to separate baby mollies from each other to keep them safe and happy.

When To Separate Baby Molly Fish?

One sign that you need to separate baby Molly fish is when they start nipping each other. When you notice the aggression, it’s time for them to go separate ways and have their own space until next time. 

Another indicator of separation needs is whether or not your fish are chasing away any new additions in your aquarium. If there seems to be a lot of activity around other fish, then it may indicate bullies. Besides this, if new fish start to locate themself in the territory of Mollies, then it is better to keep the two fishes separately.

Once you observe these signs, it’s best to separate Molly Fish from one another. When you separate these fish, they’ll each have their own spaces and won’t be able to bully any other fish that might later join the aquarium. In addition, the behavior of Mollies will change when they do not have partners around them to fight with or chase.

Even if you don’t see aggressive behaviors like nipping at all, it’s still important to keep an eye out for bullying during feeding time. If younger fish start to pick on the older counterpart, then separation should occur as soon as possible before things go out of hand.

How Long Do You Need To Separate Baby Molly Fish?

The answer to this question depends on many factors, such as the size of your tank and fish. Generally speaking, you should separate a baby Molly fish when it is around two inches long.

If you own more than one male molly fish, you will need to separate them before three months. Otherwise, they will start fighting with each other over territory.

However, if you keep them together for too long, there’s also a chance that they might become aggressive towards any little Molly fish which enters their nest. So make sure not to wait until the last moment.

One thing which often confuses pet owners is whether female Mollies can reproduce while living in different tanks or not. Well, yes, they can produce in separate tanks. But only if there are two female Molly Fish in the same tank.

If you have a bit of spare time and are willing to treat your little fishies like aquarium celebrities for a while, then you could even try breeding them. Just make sure that they attain their total growth first. Otherwise, it might cause problems.

How To Know That Baby Molly Fish Are Ready For Separation?

When the baby molly fish is about one inch long, you can separate them from their parents. It is when they start developing their personalities and will become less dependent on each other for safety. If possible, try to get at least six baby Molly Fish that are similar in size so that they won’t kill or eat one another out of hunger later on.

Baby Molly Fish will begin showing signs of being sexually mature when they are between four and six months old. It would help if you started planning on separating the babies once you see these behaviors. If you don’t, your tank may end up with overcrowding issues that lead to stress, illness, or even death among certain fish species.

How To Separate Molly Fish Baby?

Molly fish babies are incredibly vulnerable, and you have to take good care of them. The fact is that Molly Fish can be very aggressive, so they often fight with each other rather than play. So, it is best to keep the baby Molly fish separately until they are six months old.

Moreover, some tips to follow while separating baby Molly Fish are:

Ensure The Babies Are Healthy

Ensure that the baby Molly fish are healthy and in no way injured. If you find any injury on their body, it is best to separate them immediately. Make sure to give molly babies good food to eat.

Separate The Fish With Similar Temperament

Separate those babies who have similar nature when they have more than one kind of Molly fish together. It will be difficult for everyone, especially the smaller ones because bigger mollies can bully them by attacking them all the time. So ensure separation accordingly.

Keep An Eye On Them All The Time

Always keep an eye when you own these little creatures separately. It is because if you leave mollies alone, larger fishes may try to eat up small ones, or they may hurt themselves. So, regular supervision is a must to prevent bullying and ensure proper growth.

Give Them Enough Space

Another essential thing to consider is that you should give them enough space. A single Molly needs about 1.2 gallons of water to swim around freely.  Also, ensure that their tank has everything they require for their survival, such as oxygen-rich water, plenty of food, proper temperature, optimum water parameters, and perfect pH levels. All these will reduce their chances of suffering from diseases or dying.

Separate The Molly Fish That Are Too Young

If the molly fish is too young and small, then it is best to separate them. But if they are big enough, you can keep them together. Smaller fish often end up being prey for larger ones. So, keeping them separate gives these fish enough space and a healthy environment to grow safely.

Maintain Their Feeding Time And Schedule

It’s also vital that you maintain a healthy feeding schedule for baby mollies for their proper growth.  The fish that gets all the essential nutrition will grow up robust as well as healthy faster. Along will this, a healthy diet also enhances their immune system. So, any unwanted things will not happen to these little cuties.

So, while separating baby Molly Fish, you should always be careful and follow what is best for their well-being. Remember that they are your babies who depend on you to survive. You have a duty towards these creatures. So, make sure that everything goes okay until the time comes when they don’t need you anymore.

How To Keep Baby Molly Fish Healthy?

The first thing you should do is to provide her with a good home. Put some plants and stones in the tank so that Molly can hide from aggressors or end up stuck somewhere for safety. It allows your little fish to feel safe whenever she wants it, without having to worry about anything else.

Then install air bubbles on the surface of the water as this oxygenates the aquarium and makes sure Molly gets enough breathing space throughout its life cycle. Also, molly babies can live without a good filter but it is better to stay healthy and happy in the tank.

The last piece of advice we have for you is not related directly to keeping healthy but rather focusing on a comfortable living environment: Clean the tanks and change about 50% of the water in the tank weekly.

Remember, these are tiny creatures who live life through their senses, just like us humans. Unfortunately, Molly fish will die before you even notice something is wrong with her, which can lead to huge losses within a short period.

Some FAQs

What Should You Feed Baby Molly Fish?

Baby Molly Fish needs a particular type of food that is specifically for baby fish. You would want to feed your little fish the same thing you would provide them if they were in their tank. Some people like to give them live foods, but we don’t recommend it unless you are an expert on it because it can be dangerous.

What Type of Tank Does Baby Molly Fish Need?

Baby Molly fish will need a tank that is no more than five gallons. You want to make sure the lid has holes because if there isn’t any ventilation, they can die from lack of oxygen. There should also be a filter, a small heater and some decorations like rocks or plants.

What is the Temperature of Baby Molly Fish Water?

You want to make sure that your fish’s tank water stays between 78 and 82 degrees Fahrenheit. Baby mollies are sensitive to temperature changes. They can get very sick when it is too cold or hot. 

Since baby Molly fish are new to the environment, their body is not familiar with the change in the surrounding. As a result, any change will be fatal for them. Hence, you must constantly check the temperature with a thermometer all the time.

What do Baby Molly Fish Eat?

You must feed baby Mollies twice a day. It’s best to provide them small amounts over two hours or so instead of one massive feeding. It makes sure they eat slowly but still get enough food in their stomachs before bedtime. Make sure that you don’t feed them any old food because it can make them sick. You will also want to give them some vegetables like carrots, so they get a healthy diet.

How Can You Tell If A Molly Is A Male Or Female?

Males will have a dark “tear” mark that goes from the corner of their mouth to under their eyes. Females do not typically show this marking. Males are also usually more extensive and more colorful than females, but there is some overlap in these areas.

You can tell for sure if your fish is male or female by looking at its belly. Males tend to be much rounder about the ventral region (its stomach), while it’s flatter and broader on females. Thus, females look like most other kinds of aquarium fish with flat bellies when viewed from above. If you’re still unsure about whether your Molly may be a boy or girl, don’t worry too much because either way, they make great fish to have in your tank.


In short, you should only separate baby Molly Fish if they are in distress. If not, it is always best to allow the mother fish to care for her fry by herself as she would do a better job than any of us can ever hope to achieve. So basically: don’t touch – observe and enjoy. And remember that this applies to all species of fish, not just Molly Fish.

And so the answer to this question is: as long as they feel safe and secure. If you worry about any fry struggling or seem weak compared to others, then, by all means, separate them. But always remember to let nature take its course. These fish heals faster if they are in a healthy environment.

If you need any more answers, feel free to ask them in the comment section.

Good Luck!!

Happy Fishkeeping!!