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Why do Betta Fish Fight Excessively?

By 7 July 2023July 11th, 2023No Comments

Understanding the behaviour of any creature is a crucial step toward ensuring its well-being. When it comes to Betta fish, often called Siamese fighting fish, their aggressive nature is a well-known characteristic.

Let’s explore why Betta fish fight excessively, how to manage that behaviour, and introduce harmonious tankmates for these vibrant creatures.

The Social Structure of Betta Fish

Betta fish have a unique social structure that is mainly rooted in their solitary nature.

Tendency to be Solitary

Unlike many fish species that travel in schools, Betta fish evolved as solitary creatures. This solitary tendency is primarily a result of their natural environment in Southeast Asia, characterized by shallow, stagnant waters like rice paddies and flood plains. 

These waters are often isolated, forcing the Bettas to adapt to a solitary existence, which is quite different from the social structure of most fish species. This natural predisposition towards solitude contributes significantly to their aggressive behaviour when they encounter another Betta.

Territorial Defense Mechanism

Betta fish are fiercely territorial. When two males encounter each other in the wild, they will engage in aggressive displays to defend their territory. 

These displays typically involve flaring their fins, displaying vibrant colours, and even physical combat until one retreat. 

This aggressive behaviour is heightened in captivity due to the confined space of the typical aquarium. While it’s normal for them to defend their territory, it’s crucial for owners to manage this behaviour to prevent harm.

The Role of Sex and Mating in Betta Fish Aggression

Another significant contributing factor to the fighting nature of Betta fish is related to their mating behavior.

Mating Rituals and Female Betta Aggression

Although male Betta fish are notorious for their aggression, females also display aggressive behaviour, particularly during mating. 

A male Betta attracts a female by building a bubble nest. If the female accepts, she will display submissive behaviour. However, if she is not ready to spawn, she can become aggressive, leading to potential fights.

Male Aggression and Breeding

Male Betta fish are often more aggressive than their female counterparts. This aggression intensifies during breeding times when males become exceedingly territorial to guard their nests and attract females. 

They will fight off any intruding males, which can lead to excessive fighting in confined aquarium spaces.

Suitable Tankmates for Betta Fish

Betta fish, due to their aggressive tendencies, need careful consideration when introduced to a community tank. 

The choice of tankmates should ideally involve species that are non-aggressive, non-competitive and reside in different zones of the tank. Here’s an expanded look at some ideal tankmates for Betta fish.

Small, Non-aggressive Fish

Small fish with non-aggressive tendencies can cohabit well with Betta fish, given their capability to evade potential Betta confrontations swiftly.

Neon Tetras

Neon Tetras are one of the most popular choices when it comes to Betta tankmates. These brightly coloured, quick-moving fish are peaceful by nature and stay in schools, thereby offering a lower chance of individual fish being targeted by a Betta.

Cypress and Cedar Oils

These oils have been recognized for their roach-repellent properties. Cypress and cedar oils can be used in a similar manner as peppermint oil. 

Dilute these oils in water and spray the solution around the potential hiding and breeding spots of roaches. Not only will these oils deter the roaches, but they will also provide your home with a pleasant, woodsy aroma.

Harlequin Rasboras

Harlequin Rasboras are another excellent companion for Betta fish. They are non-aggressive, and their distinctive colour and patterns add a vibrant feel to the aquarium without inciting the Betta’s territorial instincts.

Non-competitive Species

Non-competitive species are those that occupy different sections of the tank and have different feeding patterns. This division helps reduce the chances of territorial disputes and confrontations over food.

Corydoras Catfish

Corydoras Catfish are bottom-dwellers, spending most of their time sifting through the substrate in search of food. 

This behaviour keeps them out of Betta’s usual territory, reducing potential clashes. Their tough armoured skin provides an extra layer of protection against Betta attacks.

Kuhli Loaches

Another excellent bottom-dwelling species, Kuhli Loaches, are nocturnal and prefer to hide during the day, which helps keep them out of a Betta’s way. Their non-aggressive nature, combined with their tendency to keep to themselves, makes them good tankmates for Betta fish.


Invertebrates can also make good tankmates for Betta fish, given their different modes of existence and feeding patterns.


Various species of snails, like Mystery Snails or Nerite Snails, are suitable tankmates for Betta fish. Their hard shells provide them with some protection from Bettas. Also, their slow pace and algae-eating habits can benefit the overall tank ecosystem.

Ghost Shrimps

Ghost Shrimps are another viable option. These small, translucent creatures often go unnoticed by Bettas due to their size and color. However, they should be introduced with care, as larger or particularly aggressive Bettas might still attempt to prey on them.

By carefully selecting tankmates and continuously monitoring their interactions, it’s possible to build a harmonious aquatic community even with the inclusion of the feisty Betta fish.

Managing Betta Fish Aggression

Betta fish’s aggression is a natural part of their behaviour, but it doesn’t mean it’s unmanageable. It’s essential to identify this behaviour and address it to ensure a peaceful cohabitation with other fish.

Identifying Signs of Excessive Aggression

Understanding when a Betta fish is showing typical aggression or when it’s becoming excessive is key to preventing serious damage. 

Some signs of excessive aggression can include incessant chasing of tankmates, biting and causing injury to other fish, flaring fins more often than usual, and not allowing other fish to feed.

Techniques to Deter Aggression

Several techniques can help reduce Betta fish aggression:

Tank Decorations

Using plenty of plants and decorations in the tank can mimic the natural environment of Betta fish. These serve as barriers and hiding spots for other fish, providing them with a sense of safety and territorial division.

Adequate Space

An overcrowded tank can exacerbate territorial disputes among Betta fish and their tankmates. Ensure the tank’s size is appropriate for the number and species of fish residing in it.

Feeding Strategies

Feed the Betta fish separately, if possible, to prevent food-based aggression. This tactic can often be achieved by dropping food at different ends of the tank simultaneously.

Calming an Aggressive Betta Fish

If a Betta fish’s aggression becomes uncontrollable and poses a threat to its tankmates, there are ways to help calm it down.

Temporary Separation

One common method is temporary separation using a tank divider or a separate tank. This separation allows the Betta fish to calm down without causing harm to others. 

During this time, monitor the Betta for any signs of illness or stress, as these can also cause aggression.

Introduce New Fish Gradually

When adding new fish to a Betta’s tank, do it gradually and monitor their interactions. It’s helpful to rearrange the tank decor when introducing new fish. This action disrupts the Betta’s established territories, making them less likely to exhibit aggressive behaviour.

By understanding and addressing Betta fish aggression, owners can ensure a peaceful and healthy environment for all inhabitants of the aquarium.