How To Control An Aggressive Molly Fish: Ultimate Guide

How To Control An Aggressive Molly Fish

Molly fish are common pets for many households. They are often docile and easy-going creatures, but this isn’t always the case. Sometimes a single Molly can become aggressive and lash out at other fishes in their tank or even humans interacting with them. So how do you control an aggressive Molly fish?

You can control an aggressive molly fish by ensuring plenty of hiding places and keeping compatible tank mates like guppies. It’s also advisable that larger, more boisterous species like cichlids don’t share the same tank (as this could trigger aggression from even docile molly types).

A good rule of thumb is that if two different species of fish have to fight to claim a territory, nothing stops them from fighting with each other.

etsy banner

This guide will walk you through how to control an aggressive Molly Fish so that you can keep him happy and healthy.

Can Molly Fish Get Aggressive?

Mollies are a species that can become very aggressive at times. Males will readily attack each other if they feel threatened or want to show their dominance.

This behavior is especially true of males as opposed to females. However, male fish are not the ones that are always aggressive either. Any molly fish of either sex can display aggression in certain situations.

For example, Molly Fish may be more aggressive when you introduce new tankmates into its environment, during mating season (if your Molly is a female), or while protecting eggs/babies (if your Molly is pregnant). These reasons all fall under the category of self-defense. The fish does these actions out of necessity rather than simply wanting to.

What Are The Signs Of Aggression In Molly Fish?

Mollies are generally peaceful, but there can be some aggression signs. These signs include:

  • Spitting at other fish.
  • Trying to attack other fish.
  • Lining up against the glass of the aquarium or tank.
  • Flaring their gills and fins.
  • Fins clamped to the body.
  • Spiky fins and the tail fin bends at the edge.
  • A female Mollie that aggressively attacks male Molly during mating season

What Makes Molly Fish Aggressive?

Mollies are a type of fish that belong to the Poeciliidae family. They usually have fusiform bodies, which makes them look like eels. If you keep molly fish in groups, they will not become aggressive as their instinct is to be social. However, if you only have one or two Mollies, they might feel threatened by any other animate object entering their territory, leading to aggression.

Some of the causes of aggression in Molly Fish are:

Diseases And Illness

Some various diseases and illnesses in molly fish can make them aggressive. If you notice your Mollies acting strange, they may have contracted a disease or condition which will require treatment for them not to be bold.

Bad Habitat

You should set up a well-planned tank with all the vital equipment before putting the molly fish inside it.  If there’s something wrong with the habitat, they might feel stressed and aggressive. So, be careful when you build up the hiding places or spaces for other inhabitants of the water tank.

Molly fish needs to have a lot of space to swim to not feel threatened. If you don’t provide this much room for them, they will become aggressive and may attack something that enters their territory or another fish constantly swimming around them.

Lack Of Food

If your molly fish are hungry, they will become aggressive. Therefore, make sure you feed them at least three times a day and even more, depending on how many of them there are in the tank. Mollies eat both plants and insects. Therefore, if there is not enough food in the tank, they will compete over food, leading to aggression.

Overcrowding

Overcrowding is one of the leading causes of aggression in molly fish. Having too many other animate objects around might make your Mollie feel threatened and cause it to attack these different creatures, whether they be living or not. 

Also, try to keep only a few numbers of live or artificial plants in the tank. Your molly doesn’t really prefer densely planted tanks that are way crowded for them even to swim in.

Keeping Them With Bigger Fishes

Think again if you’re thinking about putting Molly Fish together with bigger fishes like Guppies. But, unfortunately, it will only end badly. Even though a guppy may look small compared to a molly, its fast movements can agitate the slower moving but more aggressive-looking Mollies, resulting in an all-out war between both fish sets.

Males Bullying Females

This behavior occurs when males keep on harassing female Mollies that are spawning. It can result in the female Molly Fish not having enough energy to lay her eggs and eventually dying from exhaustion.

You cannot keep two male molly fish in the tank until and unless they have three females each. So always remember the male-to-female ratio before deciding about breeding molly fish.

Inbreeding

Suppose a fish breeder decides to breed two Mollies that are closely related. In that case, there is an increased chance of aggression among offspring due to their genetic makeup being almost identical, making them more aggressive than usual.

How to Control an Aggressive Molly Fish?

Treating aggression in molly fish is no easy task since we only know what triggers this behavior or how it looks when displayed by your pet. But after thorough research on treating aggressiveness in aquarium fishes, here are some tips you should consider if you want to get rid of the bully inside your tank.

Maintain The Tank Condition

When you consider aggression in molly fish, the first thing to do is always manage a natural habitat. Then, you can control the water conditions to mimic the molly fish’s natural habitat. Control water temperature by setting it at about 70 to 80 degrees Fahrenheit and maintain a pH level between seven point five and eight point two.

Feed Them Enough

Mollies are a type of fish that needs plenty of food. If you’re not giving them enough to eat, they might get aggressive for no reason; if this is the case, you should increase their rations to prevent any unnecessary fights at mealtime.

Quarantining Them

There are cases wherein molly fishes are aggressive. It occurs when other fish bully or threaten them in one way or the other. While it would be better to avoid bullying among our pets, there will always be times when problems arise between your Molly and its tank mates, such as guppies.

The best thing to do here is to quarantine the bully inside their own separate home where he can live freely without the risk of hurting other fish.

Increase Space

The number one reason why mollies end up being bullies is that they don’t have enough space to roam around; if you’re giving them a small tank, then chances are, your aggressive fish will fight for territory with any other pet that might wander into its area.

To avoid this problem, give your molly plenty of room by increasing the tank size as much as possible.

Avoid Odd Tank Mates

Some fish can get along well, while some do not see eye-to-eye at all, even when put inside the same home. Knowing what molly fishes are compatible with will help you determine which ones to bring the house together and which ones to leave indifferent tanks.

Aggressive tank mates include any fish that is a bit too big for the given space or has sharp teeth, so avoid buying aggressive breeds if your goal is to keep them away from fighting all the time.

Increase Decorations

One more reason pet owners fail when it comes down to treating aggression problems in aquariums, especially those who own tiny homes filled with aquatic creatures, is that they don’t provide enough decorations inside their tanks.

As a result, some pets tend not like living within such tight spaces and often display signs of hostility towards one another. Thus, it leads to fights and injuries.

By adding decorations such as fake plants and rocks, you can increase your pet’s living space. It will also distract Mollies from sparring with other fish inside the tan.

These items also provide hiding spots where aggressive fish may retreat when they feel threatened by any tank mate. Also, your mollies need live plants in the tank to feel at home; manage that.

Give Them Their Substrate

In the wild, mollies tend to live in shallow waters and often prefer gravel or sand. Thus, you must provide them with the substrate to rest while leaving most of the tank bare.

Just make sure not to give them sand since this may cause problems when your fish eat or remove the wastewater.

Instead, it would be best to consider placing rocks around the bottom, which serve as hiding places for your fish so he won’t feel threatened by other pets in his surroundings all day long.

If none of this helps, you should return any aggressive molly fish to the pet store where you got them for someone else who might be able to provide better care for these little guys than yourself. I suggest you give them a natural habitat vibe and go with gravel or sand for the molly fish tank.

How Long Does It Take To Control Aggressive Molly Fish?

Control of aggressive Molly fish is a long-term process. If you are not patient, it will be tough to control them successfully. Control can take days, weeks, or months and, in some cases, years, depending on how bad the aggression problem was when you started working with your molly fish.

Some FAQs

What Are The Most Aggressive Molly Fish?

The most aggressive Molly fish are the ones that live alone in a smaller tank without favorable water conditions and enough plants or decorations. These fish are black Molly, Gold Molly, Ballon Molly, etc.

What Is The Difference Between A Molly Fish And Other Freshwater Tropical Fish?

Molly fish are the only freshwater tropical fish that can live in brackish water, whereas most other tropical fish cannot tolerate this environment.

What Is The Natural Habitat Of Molly Fish?

Molly fish can live in a wide range of habitats. However, most commonly, they live in brackish water swamps and streams. They can also survive saltwater marshes with higher salinity than normal seawater levels.

What Are The Different Kinds Of Molly Fish?

As per experts, there are about 39 different kinds of mollies in the Poecilia genus. They range from black to green with various red, purple, and orange colors.

What Is The Maximum Size A Molly Fish Can Reach?

Mollies can grow up to four inches long in their natural habitat but may reach a length of 8inches when kept as pets in an aquarium environment. They will eat just about anything that they can fit into their mouth, including flakes, pellets, or live food.

Conclusion

Even though molly fish are sometimes aggressive, you should not avoid your pet. If this behavior suddenly appears out of nowhere without any specific reason behind it. Follow our tips above and some simple steps when setting up the aquarium right from the beginning. We believe that you will be able to find an ultimate solution to controlling your bully’s aggression while still keeping him happy and healthy inside his own home.

Hopefully, this post has helped you in some way towards understanding how to control an aggressive molly fish.

Thank you for reading!

Good Luck!

Happy Fishkeeping!!!

Scroll to Top