Can Bettas and Goldfish Live Together?

Bettas and goldfish are every aquarium enthusiast’s favorite pet fish species. So, it’s normal to get a betta and think about pairing it with a goldfish because, why not?

Well, betta fish and goldfish love interacting with people, and people love them back, but that’s where their similarities end. Betta fish species are notoriously ferocious, while goldfish are cold. While this arrangement seems like the best matchmaking possible, bringing them together is a recipe for disaster.

There’s more to why the two fish species can’t be roommates than their temperament. Read on to learn why bettas and goldfish aren’t the best tank mates.


Betta Fish and Goldfish

Bettas and goldfish are highly prized fish species in the aquarium trade. They are favorite pets, especially among children, thanks to their flowing beauty and ease of care more than cats and dogs. But that’s it!

These fish are two completely different species, from grooming requirements to temperament. So take a closer look at the two to find out what makes them so different they can’t be matched.


The goldfish you see in pet stores is a distant relative of the wild Prussian goldfish species that are native to Central Asia. It is said that there are about 125 varieties of goldfish, all of which were developed through intensive hybridization and captive crossbreeding.

Unlike bettas that are still found alive in the wild, no wild goldfish have been identified.

two goldfish

Siamese fighting fish

Bettas are members of the tropical fish family Osphoromidae native to Southeast Asia. You can find around 73 varieties of betta fish, mainly bred in captivity and intensely hybridized to create the glamorous fins and spectacular colors most fish lovers desire.

These domesticated fish exist in the wild, unlike the artificially bred goldfish.

Siamese fighting fish

8 Reasons Why Betta Fish and Goldfish Shouldn’t Live Together

1. Temperament

Bettas are also known as “Siamese Fighting Fish” for a number of reasons. This species of fish lives by one rule: anything in the water is the enemy.

Male bettas are known to be aggressive, very territorial, and domineering, attacking and defending themselves from anything that swims, even the easygoing goldfish. Their fighting tendencies date back to the 1880s in Thailand when locals kept hickeys specifically for fighting.

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Bettas and goldfish will be intentionally placed together so that spectators can bet on who will win the fight. Unfortunately, modern bettas are no different from their ancestors, which means that goldfish will most likely scare them if they share territory, provoking aggression.

Goldfish, on the other hand, are peaceful animals, although most varieties can become fin nippers, a trait that bettas dislike. The goldfish will bite the betta’s fin, and if it’s not the type of fin that bites, the betta may even attack it.

red betta fish

2. Water Temperature Difference

Bettas may look angry and fierce, but don’t let that fool you into thinking they’re tough and tough when it comes to water conditions.

They are ideal tropical fish that need warm water temperatures of around 75 to 86 degrees Fahrenheit to thrive and be happy. Anything outside this range can put them under severe stress and result in death.

Water dropping below 75 degrees can cause a temperature shock to your betta. This will slow down the body’s metabolic rate, cause it to stop eating, and become very lethargic. This condition will impede circulation due to inactivity, which can trigger diseases such as fin rot.

Goldfish, on the other hand, prefer cold water, with temperatures between 65 and 72 degrees Fahrenheit. Higher temperatures above 72 degrees can make goldfish sick due to increased metabolism. These fish need different water temperatures to survive, the reason why they can’t be tankmates.

3. water hardness

You can determine whether water is hard or soft depending on its mineral content. Fish need minerals in their water as part of their nutritional needs, but not all species have the same mineral preferences and tolerance levels.

For example, betta thrives in soft water with almost no calcium and the water’s PH level is close to 7.0. The lower the amount of calcium, the lower the PH level, and the happier the betta is. However, goldfish prefer an aquarium with a higher calcium content and a higher PH level from 7.2 to 7.6.

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4. Goldfish “Too Dirty” for Bettas

Goldfish excrete too much waste which increases ammonia levels in the water, making them “dirty” creatures. This is because they lack stomachs, so whatever they ingest goes straight through the fish into the water.

For this reason, tanks require a proper filtration system that can control the nitrogen cycle and manage waste. Pet parents should also change the water frequently to keep the tank clean, a process that can be stressful for your betta and ultimately affect its immunity.

Plus, bettas are generally clean and don’t grow well in dirty water. As a result, they are very sensitive to ammonia, which means high levels can cause ammonia poisoning and kill them.

goldfish dirty tank_JenJ_Payless_Shutterstock

5. Goldfish Need a Big Aquarium

If you have a betta, you should put it in a tank of about 5-10 gallons. Bettas are small, growing to 2 inches or more, so the size of a tank like that gives them enough room to thrive.

However, goldfish can grow to 6-8 inches in captivity and 12 inches in the wild, requiring a larger tank, no less than 20 gallons.

The difference in size means tank decorations such as hiding places, plants, caves, and ornaments that match goldfish will not work for the betta, a very important factor for the fish’s lifestyle.

6. Water Flow Rate

Goldfish tanks require a sufficiently strong water flow to ensure an adequate level of circulation through the filter system. It is important to keep the water clean.

While goldfish are fine with high flow rates, your betta doesn’t like strong water movements. This species of fish has long, flowing fins that look spectacular, but mostly don’t help with swimming.

Bettas will struggle to swim in stronger currents thanks to their heavy fins. Living in an environment that restricts his movement and being constantly hit by water from side to side will stress him out. That could expose him to health problems.

7. Bettas are Small Fish

As you may have noted earlier, goldfish are larger than bettas. Goldfish are omnivores, and it is not a good idea to house them with small fish that can fit in their mouths.

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Betta fish surrounded by aquatic plants

8. Goldfish Eat Quickly & Without Discrimination

Bettas are carnivores and don’t really like plants. This species of fish requires more protein in their diet, so they prefer to chew meat more.

On the other hand, carp which are omnivores have no problem devouring a delicious mix of plant matter and meat. They are also quick opportunistic feeders and can eat anything you give them, including betta food.

They may starve your betta. Worse still, the two species differ in terms of dietary requirements; feeding betta goldfish or vice versa will potentially harm them. For example, bettas can eat too much vegetation than they should, whereas goldfish eat too much meat, leading to dietary imbalances and potential health problems.

Can You Put Bettas and Goldfish Together Temporarily?

You can keep both of them temporarily in the same aquarium, only if the situation is dire. For example, it’s possible that the betta’s tank heater failed, so you put it in the goldfish’s tank while you were repairing it.

This shouldn’t be a thing of the past, and is HIGHLY discouraged. However, you can set up a standby transfer tank or take it to the vet’s tank if you have to swap one out.

Don’t just put them together for convenience, because one may end up seriously injured, sick, or dead!

fish bowl divider


You don’t have any reason to keep your betta and goldfish in the same cage. These fish species have different needs and can generally be hostile to each other.

You can only allow them to share temporary housing if the situation allows.

Related Read: Can Two Female Bettas Live Together?