Will a Betta Fish Kill a Goldfish? {Find Out Why}

Many people wonder if a betta fish will harm a goldfish. It is a common question that arises due to the different behaviors and characteristics of these two types of fish.

Will a betta fish kill a goldfish? Understanding the nature of betta fish and goldfish in this article can help shed light on the potential interactions between them.

Will a Betta Fish Kill a Goldfish?

Yes, it’s highly likely that a betta fish will attack and potentially kill a goldfish if they are housed together in the same tank.

Betta fish are known to be aggressive and territorial, especially towards other fish with:

  • long fins
  • bright colors
  • similar body shapes

Goldfish, on the other hand, are:

  • generally peaceful
  • unable to defend themselves against the aggressive nature of a betta fish

Betta fish require warm water temperatures ranging from 75 to 80 degrees Fahrenheit (24 to 27 degrees Celsius), while goldfish thrive in cooler water temperatures between 65 and 72 degrees Fahrenheit (18 to 22 degrees Celsius).

Can a Betta Fish Live with Goldfish?

No. Compatibility between betta fish and goldfish is generally not recommended due to several factors.

  1. Betta fish are known for their aggressive nature and territorial behavior, which can result in them attacking and potentially killing goldfish.
  2. Their long fins, bright colors, and similar body shapes may trigger aggression in bettas.
  3. Bettas prefer warmer water temperatures, while goldfish thrive in cooler waters, making it challenging to maintain suitable conditions for both species in the same tank.

To ensure the well-being of both fish, it is advisable to provide separate tanks for bettas and goldfish.

What Happens if You Put a Betta Fish with a Goldfish?

Housing a betta fish with a goldfish can lead to aggression and harm.

  1. Betta fish are highly territorial and may perceive goldfish as intruders, resulting in attacks.
  2. Betta fish are equipped with sharp teeth and can inflict damage on the delicate fins and body of goldfish. The goldfish, being generally peaceful, may struggle to defend themselves.
  3. In most cases, the outcome is detrimental for the goldfish, as they are more vulnerable to the aggressive behavior of the betta.

To avoid any potential harm or stress, it is best to keep bettas and goldfish in separate tanks.

Why Do Betta Fish Kill Goldfish?

Answer: Betta fish are known to exhibit aggressive behavior towards other fish, including goldfish. Several factors contribute to their aggressive nature.

Betta fish are highly territorial and will fiercely defend their space, perceiving other fish as threats or competitors. Goldfish, with their long fins, bright colors, and similar body shapes, can trigger the aggressive instincts of bettas.

Bettas have a labyrinth organ that allows them to breathe oxygen directly from the air, enabling them to survive in stagnant water conditions.

Goldfish, on the other hand, require well-oxygenated water. These differences in behavior, appearance, and environmental needs increase the likelihood of betta fish attacking and potentially killing goldfish.

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Can Betta Fish and Goldfish Be Kept in Separate Tanks but Side by Side?

Yes. Keeping betta fish and goldfish in separate tanks but placing them side by side is generally a safer approach than cohabitation.

This setup allows you to appreciate both species without risking aggression or harm. It is important to ensure that each tank provides suitable conditions for the respective species, including:

  • temperature
  • filtration
  • appropriate tank sizes

Keeping the tanks side by side can still provide visual stimulation and interaction between the fish without physical contact.

Monitor the behavior of each fish closely. In some cases, betta fish may still perceive the presence of goldfish as a threat, leading to stress or aggression.

If any signs of distress or aggression are observed, consider increasing the distance between the tanks or using visual barriers to reduce stimulation.

Can Betta Fish Eat Goldfish Food?

No. Betta fish and goldfish have distinct dietary needs due to their different biological characteristics and nutritional requirements.

1. Betta Fish Diet

Betta fish are carnivorous and thrive on a protein-rich diet. They require specialized betta pellets or betta fish flakes, which are formulated to provide essential nutrients for their optimal health and growth.

2. Goldfish Diet

Goldfish are omnivorous, needing a balanced diet that includes both plant matter and protein sources. Goldfish-specific pellets or flakes are designed to meet their nutritional needs, supporting their growth and overall well-being.

3. Avoid Interchanging Foods

Feeding betta fish with goldfish food or vice versa can lead to nutritional imbalances and health issues. Betta fish may lack sufficient protein, while goldfish may miss out on necessary plant-based nutrients.

Can Betta Fish Live with Guppies?

Betta fish and guppies can
potentially coexist in the same tank, but it is not without risks. Here’s what you need to consider:

1. Tank Size and Setup

Provide a tank that is spacious enough to accommodate both species comfortably. A tank with plenty of hiding spots and visual barriers can help reduce aggression.

2. Compatibility

Male bettas are generally more aggressive and may see the colorful, long-finned guppies as rivals, potentially leading to aggression. Female bettas are usually less aggressive and may have a higher chance of peacefully cohabitating with guppies.

3. Monitoring Behavior

Monitor their interactions closely. If the betta fish displays aggressive behavior, such as chasing or fin-nipping, it is crucial to separate them to prevent injuries.

4. Feeding

Ensure each species receives appropriate food. Bettas require a protein-rich diet, while guppies are omnivorous. Feed them species-specific food to meet their nutritional needs.

Can Betta Fish Live with Glofish?

Glofish, which are genetically modified zebrafish, have similar care requirements to regular zebrafish. However, cohabitation with betta fish can be challenging due to their differences:

1. Aggression

Betta fish are known to be aggressive, and they may perceive the bright colors and active nature of glofish as threats, potentially leading to aggression.

2. Tank Size and Setup

Provide a spacious tank with plenty of hiding spots and visual barriers. This can help reduce stress and potential aggression between the two species.

3. Monitoring Behavior

Observe their interactions closely. If the betta fish displays aggressive behavior towards the glofish, it is advisable to separate them to prevent harm.

4. Water Conditions

Ensure the tank provides suitable water parameters for both species. Glofish and betta fish have slightly different preferences in terms of temperature and water quality, so maintaining suitable conditions for both can be challenging.


While betta fish are known for their aggressive tendencies, it is generally recommended to provide separate tanks for bettas and goldfish to ensure their safety and minimize any potential harm.

Taking appropriate precautions and understanding the unique needs of each species can help create a harmonious and healthy environment for both fish.


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Brian Arial

Brian Arial has kept fish for leisure and worked with fish stores for most of his life. He enjoys writing and caring for aquariums and ponds.