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Are Molly Fish Aggressive? You Should Know This!



Are Molly Fish Aggressive

The temperament of a fish species helps determine several things while keeping it in an aquarium. It gives a decisive effect for the aquarist to know whether the fish must be kept alone or in a community tank, whether it requires plants or not, and the pivotal species which it is compatible with. So it is best to know rather than add different species of fish together recklessly. 

Mollies are one of the favorite fish species in the aquarium hobby. It is a hardy species of fish making it one of the best species for beginners. They come in a variety of types and have different colors. But what about their behavior and temperament? Are they aggressive or not? Well, let us move on to find out.

Are Molly Fish Aggressive? 

Mollies are not aggressive. They come as peaceful species of fish and won’t bother other species of fish. Although this doesn’t mean that they don’t have hostility in their blood. If the situation demands it or things don’t go their way Mollies can get aggressive. 

One instance is that if you keep Mollies in an overcrowded tank, then they will show signs of aggression. The same thing goes if you have paired them up with other aggressive fishes. They won’t hesitate to nip the fins of other fishes if the circumstances are not to their liking.

Are Mollies aggressive towards other Mollies? 

Unless you overcrowd a tank, Mollies are not likely to show aggressive behavior. Mollies love the company of their kind and do well if kept in a group. Although don’t make the mistake of keeping male Mollies together in a tank. Males tend to show aggression towards each other. 

The males show aggression towards each other in moments such as while eating, mating, etc. So in a tank always keep the ratio of the females greater than the males. One male with three females is the magic number.

Why do Male Mollies show aggression towards each other? 

As you already know, male mollies in a single tank will show aggression towards one another. This behavior can be stimulated by several causes. 

The first thing is if the tank is small. When the tank size is not adequate for the male Mollies, they cant maintain or make their territory properly. So territory is also a cause for Male mollies to become hostile towards one another. 

The second thing is mating. If you have one female and two males in a tank, then get ready for some action. The males will fight for the female to reproduce. This aggression is mainly to get the attention of the female to breed.

Are Female mollies aggressive? 

Female mollies are not aggressive. They are peaceful and don’t show aggression towards other females, contrary to the males. 

Although females are capable of showing aggressive behavior. Females will show hostile behavior if the aquarium is overcrowded. It is primarily because they go under stress if the tank is crammed. Also, if they are shown aggression by other fishes, females don’t hold back in expressing hostility. 

Females can also become aggressive when they are pregnant. This is also mainly due to stress. While pregnant female Mollies prefer solitude and become alert as well. After pregnancy, the females go back to their carefree peaceful nature.

Why do male Mollies chase females? 

Sometimes you can witness male Mollies chasing the females. This is a natural behavior of the Mollies and has nothing to do with aggression. The only reason a male chases a female is due to breeding. The male seeks the attention of the female and doesn’t resort to anything that can hurt the female. So a male chasing a female is nothing to worry about.

Tank Mates for Mollies

So after going through the temperament of the Mollies, it is essential to pair them with peaceful species of fish. If paired with aggressive ones then Mollies becomes aggressive. Also, avoid overcrowding a tank with Mollies, they get stressed and show aggression. 

So the best tankmates for Mollies are Guppies, Tetras, Swordtails, Platys, Danios, and Cichlids like Dwarf Cichlids, and Keyhole Cichlids. 

Can you keep several Mollies together? 

If you want to keep Mollies in your aquarium, you should always keep them in a group. Keeping a sole Molly is not a good thing. As they are community fish, Mollies if kept alone will not lead a good life. They will become stressed and depressed. 

You should have at least four Mollies. This is the minimum number of Mollies to keep in a tank. The next important thing is to have one male and three females. If you keep a greater number of males, the males will show aggression towards each other for territory and mating. Never keep two males and one female Molly. The males will fight vigorously for the female for reproduction. 


In the end, we can say that Mollies are peaceful fishes that live minding their own business. Mollies are peaceful fishes that don’t waste their time bothering other fishes. They will show aggression if they are bullied by other species.

Overcrowding is a big no with Mollies, otherwise, they will become aggressive and nip the fins of other fishes. The males are also aggressive towards one another, so keeping many males in a tank is not fit. Females are peaceful but can show aggressive behavior when pregnant.

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