Why Do Molly Fish Chase Each Other?

Molly fish are a group of small freshwater live-bearing tooth carps in the family Poeciliidae. Usually, Molly fish are social and friendly that enjoy when they have company. But why does Molly fish chase each other?

The chasing behavior of Molly fish can be a sign of sexual arousal in Molly fish. Molly fish chase each other to establish dominance or territory. But this behavior also helps Molly Fish develop better social skills by reading their opponent’s situation and body language. In addition, some Molly fish chase each other to mate and can display courtship behavior during this process.

In this blog post, we will be discussing Molly fish and why these fish chase each other.

Can You Keep Molly Fish With Other Mollies?

Mollies are peaceful fish that lives in tropical climates. You can keep them with other fish as well in your tank.

However, you will need to make sure the tank is big enough for them all. Molly fish like to live freely in their own space. So they must have alone time during the day if they want it. These Fish are also schooling fish, so keeping them in groups is normal.

How Many Molly Fish Can You Keep In A Tank?

Molly fish tends to do better when you keep them in at least five or more groups. But the numbers should not go over ten for each type. These fish show aggressive behavior if their group size gets too small and fight with other molly fish for dominance within the tank.

Molly fish may fight, injure and even kill other fish in a tank. They are also more likely to attack each other if their water is too dirty or they don’t have enough hiding places. These fish needs plenty of places to hide and swim. Molly fish will often feel stressed in a tank with no hiding spots or if they are unable to swim freely without bumping into objects.

Do Molly Fish Chase Each Other?

Molly fish are very peaceful creatures who tend to have difficulty getting along with their tankmates. They will usually get along well in a community tank but often. But you may find Molly Fish chasing each other around the aquarium. Unfortunately, these fish chasing each other can lead to Molly fish biting, and this is a problem that Tanks tend to have more than most.

Why Do Molly Fish Chasee Each Other?

Molly Fish are infamous for their aggressive nature, especially when establishing territory. Unfortunately, these Fish are among the more temperamental species available in home aquariums today. Not only does Molly Fish have a reputation for being territorial, but they also seem to enjoy chasing each other around the tank.

However, some of the reasons Molly fish chase each other are:

To Breed

Molly fish do not mate like humans. Instead, these fish reproduce by the male releasing sperm and the female releasing eggs simultaneously. This means that Molly Fish can breed in a group or pairs.

When Molly Fish chooses to breed as a pair, they often chase each other until one gives up and allows for breeding. Usually, Mollies display aggressive behavior when it comes time for mating.

For Food

Molly Fish will often go after smaller prey if they see something that seems like it would make a good meal. They may also instinctively chase after other Molly fish to establish dominance in the tank. These fish will chase away other fish during feeding time.

For Fun

Molly fish are pretty active, and they may enjoy chasing one another around the tank as a form of play. Some Mollies might chirp at each other in the wild too. Thus, many people believe that Molly fish use sounds to communicate with one another outside of visual cues alone.

Due To Stress

Molly Fish are sensitive when it comes to environmental changes. So if something is off in the tank, such as water temperature or available food, Molly fish may feel stressed and begin chasing each other around.

For Territorial Reasons

Molly fish will often chase each other around the tank for territorial reasons. Many people observe Molly Fish chasing one another out of their way to lay claim on a specific part of the aquarium or even over food. These fish will also chase each other out of the way if there is not enough space for everyone to live comfortably in their tank.

For Protection

Molly fish are commonly a delicious prey for more giant species, like Cichlids or Oscars. So these fish often try and circle one another when they feel threatened. This act makes them look bigger than they are.

Molly Fish may also chase each other around the tank to protect their fry or when Molly fish are trying to keep a potential predator away from their eggs.

To Establish Dominance

Sometimes Molly fish can become more aggressive than other species of tropical fish. It usually occurs when you introduce Mollies suddenly to a new tank where there are aggressive tankmates. Molly fish establish their hierarchies within groups by fighting it out with others. The dominant Molly Fish will then claim the tank as their home, while Molly fish, defeated in battle, become subordinates.

Is It Harmful When Molly Fish Chase Each Other?

Molly fish (Poecilia spp.) are small, colorful aquarium fish. They can grow to about four inches in length and often live for three or more years.

Molly Fish will sometimes chase each other. This is normal behavior of Molly Fish when they engage in mating rituals. But sometimes, tracking behavior can be harmful because of the following reasons:

  • First, mollies can bite and harm each other during mating rituals.
  • Second, they may feel too stressed to eat and starve if chased.
  • Finally, chasing behavior can injure and wound up Mollies.
  • Chasing Molly Fish behavior can lead to injuries and death of the fish. In addition, the fish are more likely to bump into the hard surface of the aquarium, and changing that can cause injuries and wounds.
  • Excessive chasing makes Molly fish aggressive. As a result, such fish are more likely to attack their tankmates.

How To Keep Many Molly Fish Safe In Tank?

Molly fish are small yet extremely friendly and active freshwater fish that can live in aquariums. Molly Fish is very delightful to look at due to its brilliant colors. But they also require proper care as all other creatures do.

A few steps to keep Molly fish safe in the tank with each other are:

  • First, give Mollies enough space to swim. Molly fish are very active, and they need tanks with enough room to swim freely. Mollies will bump into each other and hurt themselves if they cannot have enough space to swim.
  • You may keep Molly Fish of the same size in the tank. But avoid keeping too many Molly Fish together as it will make others feel insecure and stressed out, leading to possible diseases like fin rot.
  • It is best to keep Mollies in tanks containing only Molly Fish. They are peaceful creatures, so they don’t like interacting with aggressive fishes that may harm them or disturb their activities.
  • Keep the tank water at the optimum condition with regular water changes. Don’t forget to maintain the temperature at about 70- 80 °F and a pH level of around 7-8.
  • Provide enough food for all the Molly Fish. Molly fish are omnivorous, so they need plant-based foods and meaty food items to ensure proper nutrition.

Some FAQs

Can You Keep Molly Fish With Other Fishes?

Molly fish are a relatively docile species, but they tend to be territorial. However, Molly Fish can often get along with other fishes in the same tank if there is plenty of space for them and enough hiding places from which Molly Fish won’t feel threatened.

What Are The Best Tankmates For Molly Fish?

When you keep Molly fish with other species, try to choose those with similar size and temperament. As Molly fish mature, they are more vulnerable and aggressive. So, it is best to keep them alone.

However, some fishes that you can keep with Mollies are Platies and Guppies.

Do Molly Fish Bite?

Molly fish are generally peaceful, but they have teeth and can bite if you startle or stress them. It is best always to use a net when catching Molly fish. It will reduce the chances of getting bites when you clean the tank or remove the fish. Some Molly species, such as Sailfin Molly, are more aggressive than the Common Molly, so always research your particular species.

What Types Of Fishes Do Not Get Along With Molly Fish?

Mollies are generally peaceful fish, but they can become territorial once these fish reach maturity. Therefore, it would be best if you never kept Molly fish with large, aggressive species such as Cichlids or Oscars.

Molly Fish will usually lose the fight if put in this environment. However, some fast-swimming fish like Guppies can nip fish with long, flowing fins like Sailfin Molly.

What Molly Fish Are The Best For Beginners?

Molly fish are a good choice for beginners as they adapt well to new environments. These fish do not need special feeding or care. You can keep them in a community tank with other species of similar size, temperaments, and water needs so long as there is enough space for Molly fish to set up their territory.


Although Mollies can be territorial, they stress out more quickly than other fishes. Therefore, they must have the right environment to stay happy and healthy. If you follow these guidelines, Molly will live a long life filled with happiness!

Hopefully, this post gave you a better understanding of Molly fish and a bit about their behaviors. Do not forget to share this post on your social profiles!

I hope you enjoyed reading this blog as much as I liked writing. If you have any questions or comments, please leave them below, and I will try my best to answer everyone’s concerns promptly.

Thanks for stopping by, and good luck with Molly fish!

Happy Fishkeeping!!!