Why Are My Female Mollies Chasing Each Other

Have you noticed that your female Mollies are chasing each other?

Are you afraid that this could be a negative sign from your Mollies? In this article, I will explain all the possible reasons why your Mollies are chasing each other.

Why Are My Female Mollies Chasing Each Other? Female Mollies chase each other when they quarrel. This happens once in a while and is generally over quick.

Most times, you don’t need to worry about separating them. However, if you notice they are hurting each other, you can decide to step in.

Female Mollies Chasing Each Other

Is My Molly Pregnant? How To Tell

If you spot that your Mollies have a swollen belly, then it is likely pregnant. This is the easiest and most apparent sign of pregnancy. Other signs you notice when your Mollies are pregnant includes:

  • Blackish line or spots running down their stomach
  • Plumper and rounder bodies
  • Change in behavior 

If your Mollies are pregnant,
you should also notice a blackish line or spots running down their stomach. This black spot or line is the eye of the fry. The body of your pregnant Mollies will also continue getting rounder and plumper as pregnancy progresses.

Also, check if a dark triangular spot appears near the anal vent. Ensure you observe your Mollies during this period to confirm their status.

During pregnancy, your Mollies will develop certain behavioral changes. Ensure you lookout for these changes. Some of the behavioral changes you may observe are slower movement in the water, more food consumption, and avoiding other fish in the tank.

Once you notice this, ensure you are there for your pregnant Mollies and help them in times when they may be too weak to go about their normal daily routine.

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Why Are My Female Mollies Fighting?

If you find your female Mollies fighting, it may be because of their diet. If they don’t feed well or rest well, they could be stressed and get aggressive.

Some of the other reasons why your Mollies are fighting includes:

  • They are new to the environment
  • They are trying to get to know each other
  • You have a bad seed in the tank.

Naturally, it’s the male Mollies that fight and chase each other. They do this for territorial purposes when they fight with other males or as a mating ritual when chasing the female Mollies. For the male Mollies, this is normal.

As much as the male Mollies are natural fighters in the tank, the females may fight once in a while. However, when you find female Mollies being aggressive with each other, you need to observe them.

When female Mollies fight, it doesn’t last long. But if this persists, then you have to take matters into your hands. Check their diet and ensure they get plenty of vegetables in their diet.

Also, check the keeping condition of their tank. If the keeping condition is not right, your Mollies could get frustrated, and that could make them fight.

Also, if they are newly introduced to the tank, they may take a while to get to know themselves. You can step in and step into the fights if they get too aggressive.

What Should You Do?

If you are worried about your Mollies fighting and hurting themselves, the best solution is to separate them. Quarantining them may solve the problem permanently. You could try floating the Mollies in a container daily.

One of the Mollies should be floated in the container overnight and the other in the morning. After some days, you can let them back into the water.

If it’s just one of your Mollies that’s being aggressive; you could quarantine only that one, then switch off the light in the tank to redecorate it. After some days, you can reintroduce the quarantined Molly back to the water.

Increasing the male population in the water is another good way to stop your female Mollies from fighting. With the increased number of males, your female Mollies will have a lot on their hands and won’t have the time to fight each other.

Will The Female Mollies Be Aggressive To Other Fish?

Female Mollies are naturally peaceful but can also be aggressive fish to themselves and other fish, especially in more confined tanks. If Mollies don’t have enough space, it will be hard to stay away from themselves and other fish.

This will result in them getting initiated and fighting with the other fishes in the tank. When they are stressed, they won’t hesitate to attack other fish. They may even kill these fishes if they are bigger than the other fishes.

Your Mollies get stressed when the keeping conditions in the water are not right. This includes high levels of ammonia and nitrates.

When you observe your Mollies be aggressive with other fishes, check the keeping conditions in the tank. If all is fine and your Mollies continue bullying your other fishes, keep them from each other.

Can I Keep Two Female Mollies Together?

Yes, you can keep two female Mollies together. Mollies are peaceful fishes when living together and can tolerate each other very well. The females are not naturally aggressive, so putting them together shouldn’t be a problem.

When you newly introduce your female Mollies to each other, you may see your female Mollies fighting once in a while. This doesn’t last and won’t put them at risk. However, if they become too aggressive, do not hesitate to separate them.

Also, before introducing your new female Mollies to other female Mollies, ensure that the living conditions in the tank are just fine.

The reason for this is that new Mollies may react to a poorly maintained keeping condition, which may trigger it and make it aggressive.

How Many Mollies Should You Keep Together?

For your Mollies to live comfortably with each other, you should keep them in a group of four. This is because Mollies love to stick with themselves. Each molly will require at least three additional gallons for themselves.

If you plan on having more than four Mollies in one tank, then ensure that the tank is big enough. The tank should be at least twenty gallons or more, depending on the size of the aquarium you want.

The fact that Mollies are very social and love to keep a school should be carefully considered before starting your aquarium.

If you have a large aquarium, ensure you pay close attention to it. Ensure you clean it out regularly, and take away the leftover food as soon as you can. Remove dead fishes from the water and ensure you change the water regularly.

But doing this, you save your Mollies from poisoning or diseases caused by organic matter from their bodies, the dead Mollies in the water, or from leftover food.

This way, having more Mollies in the aquarium won’t be a problem.


Hello, I'm Jason. I'm the guy behind HelpUsFish.com. I volunteer at my local fish shop and I created this site to offer tips and advice on the fish I care for.