Can bettas live with goldfish?
That’s a question many novice fish keepers ask themselves when they first start. After all, betta fish and goldfish are both stunning to look at. And a combination of the two species would make a beautiful display.
In this guide, we compare and contrast the two species’ requirements and temperaments to see whether bettas and goldfish would make good tankmates.
Can bettas get along with goldfish?
Male betta fish are highly territorial. They won’t tolerate other fish that they view as competitors who are invading their space. Of course, temperament depends on the individual fish, and some bettas are more aggressive than others.
However, even if your betta is the most chilled-out dude in the tank, goldfish are a whole different ball game. Although goldfish are not overtly aggressive, they are well known as fin nippers. Your betta’s glorious, trailing fins and tail would be a prime target for a goldfish.
Also, bettas tend to regard any fish that’s brightly colored and has trailing fins or tails as a potential threat and will often attack it. That makes it out of the question to even consider keeping fancy goldfish or fantails with a betta.
So, it’s reasonably safe to say that, temperament-wise, bettas and goldfish do not make good tankmates.
Goldfish need much more space than bettas. So, a ten-gallon Betta Tank Setup: Your Quick and Easy Guide would be great for a betta. But if you added a couple of goldfish, things would soon become cramped.
As we’ve mentioned, common and fancy goldfish can grow to be up to a whopping 12 inches in length, requiring a tank of at least 30 gallons or more. Remember that you’ll need to add a further 12 gallons to your tank capacity per new goldfish.
Now, although your goldfish might be tiny when you first bring them home, they will grow rapidly, and you’ll very soon find yourself having to upsize your tank to accommodate the goldfish.
Betta and goldfish sizes
Betta fish are small, growing to around one to two inches in length and between half to three-quarters of an inch in depth.
In comparison, goldfish are much bigger creatures, with some specimens reaching a length of up to 12 inches, depending on the variety. Large goldfish have proportionately big mouths, and the really big ones could easily swallow a betta fish whole.
Apart from the slow-swimming fancy and fantail goldfish, other types, such as comets, are much faster swimmers than bettas. So, your poor betta fish could be an easy target for a large, hungry goldfish.
Goldfish and betta diets
Goldfish have huge appetites. Although they are primarily vegetarian, they will eat meat too, devouring pretty much anything that comes onto their radar.
Although goldfish do spend much of their time rooting around in the substrate looking for food, they will also make frequent trips to the surface, and that brings them into direct conflict with your betta, who is a confirmed surface feeder.
So, you will find it very difficult to make sure that your betta gets enough food and that your goldfish don’t eat too much!
The most obvious difference between betta fish and goldfish is that bettas are tropical and goldfish are, technically speaking, cold-water fish. Keeping fish in water that is outside of the species’ preferred temperature range can cause adverse health effects, including an impaired immune system. That makes the fish more susceptible to disease.
Goldfish are a member of the carp family and are native to East Asia. Ornamental goldfish were first selectively bred over 1,000 years ago in China and were kept in ponds as decoration.
Goldfish can live in a fish tank in your home, but they are just as happy to live in a community in an outdoor pond in your garden. When the weather is very cold, and the water temperature drops, the goldfish move into deeper water where they can shelter among vegetation. Goldfish can survive happily in a pond, even when the surface of the water freezes over!
In summer, when the weather is very hot, goldfish seek out deep water where it’s cooler, coming to the surface only to feed and snatch insects that have settled on the water.
So, the preferred water temperature for goldfish is between 650 and 750 Fahrenheit. Indoor goldfish don’t need a heater in their tank, as room temperature is usually perfectly fine for their needs.
Bettas are native to Laos, Cambodia, Vietnam, and the Mekong basin of Thailand. Wild betta fish live in rice paddies, floodplains, and shallow ponds.
The preferred water temperature for bettas is between 780 and 800 Fahrenheit. Bettas are highly vulnerable to temperature shock. So, if the tank temperature falls below 740 for long periods, your fishy friend’s immune system could be compromised. That will leave him wide open to attack by bacterial diseases.
Unlike goldfish, which benefit from seasonal temperature fluctuations, betta fish need a constant, stable temperature to remain healthy and happy. That’s why you should always place your betta tank’s heater close to the filtration system, so that warm water is circulated evenly throughout the tank. Put your tank thermometer at the opposite end of the tank to the heater to make sure that the water is the same temperature throughout the habitat.
How does the wrong water temperature affect bettas and goldfish?
So, if you have your tank at the perfect temperature for your betta, it will be too warm for your goldfish, and their metabolism will rise, potentially shortening the goldfish’s lifespan. Also, your goldfish would require more food, which in turn will produce even more waste, potentially leading to poor water quality and ammonia spikes.
If you were to keep your betta fish at a lower temperature than the ideal, he would become extremely lethargic, barely able to swim. That’s a big problem because bettas must swim to the surface of the tank to feed and to breathe air through their labyrinth organ. Being unable to feed and breathe properly will very quickly kill your fish.
Prolonged exposure to water that is too cold causes several nasty health problems for betta fish. Bettas have long, flowing fins and tails that have poor circulation at the extremities. When the water temperature is too low, the circulation may cease altogether, causing the ends of the fins to die and allowing a condition called fin-rot to set in.
Also, bettas are prone to swim bladder disease. The swim bladder is a sac inside the fish that is filled with air, allowing the betta to rise up and down in the water. If the water in the tank is too cold, your betta won’t be able to digest his food properly.
Poor digestion causes the fish’s stomach to swell, which in turn presses on the swim bladder. The swim bladder ceases to function properly, leaving the fish disabled and either trapped on the bottom or floating helplessly on the water’s surface.
All fish have to live in water. However, the type of water, in terms of water hardness, that different fish species need to thrive varies.
“Water hardness” mainly refers to TDS, or Total Dissolved Solids, and the various minerals and impurities that comprise the element. Common minerals that are found in water include lead, calcium, copper, and other non-harmful components.
Fish take the minerals that they need to survive from the water. Some species of fish find it more difficult to extract those minerals than others. Those need to live in harder water, which makes the process of mineral extraction easier. So, even if the fish is not very efficient at obtaining minerals from the water, it can still get the amount that it needs to remain in good health.
Betta fish prefer soft water that contains little to no calcium. Calcium content, also referred to as kH, affects the buffering capacity of the water. The lower the calcium content, the lower the pH level of the water will be, and bettas need a low pH of 7 to thrive.
However, goldfish prefer moderately hard water, which is typically 200 to 400 ppm TDS away from the betta fish’s ideal environment. Goldfish also need water that has a high pH of between 7.2 – 7.6, meaning that the water will have a high calcium content.
So, you can see that betta fish and goldfish are incompatible when it comes to the water quality that they need to stay healthy.
The strength of the water current in the tank is another important consideration for both bettas and goldfish.
Betta fish are typically not very strong swimmers and will struggle if the filter flow is too powerful. Ideally, the flow in a betta tank should be low to zero. So, your filter should have a baffle to restrict the current without affecting the flow, or you could use a gently bubbling sponge filtration system instead.
However, goldfish prefer a medium to high water flow, apparently enjoying playing around in the current that’s created by the filter. Also, goldfish tend to produce a huge amount of waste products, and a sponge filter system won’t cope with that level of waste production.
As mentioned above, goldfish are very dirty fish, producing vast amounts of waste. Goldfish don’t have stomachs, so everything they eat passes straight through them. That dramatically increases the risk of ammonia spikes, and although bettas are relatively hardy fish, they are highly susceptible to ammonia poisoning, and that will quickly kill your fishy friend.
Because they are so dirty, a tank that has goldfish in it requires frequent water changes to keep the ammonia levels down. Unfortunately, frequent water changes will stress your betta fish, potentially compromising his immune system and leaving him open to attack by bacterial and parasitical disease.
Also, to keep your tank clean and minimize harmful levels of ammonia, you will need a powerful filter with a strong flow rate. While that will suit your goldfish, your betta won’t be able to cope with the powerful current and will become even more stressed.
When it comes to décor in your tank, goldfish and betta fish have different likes and dislikes. Betta fish enjoy a heavily planted tank that offers plenty of hiding places and areas to rest in. Because of the betta’s habit of surface feeding and surface breathing, a collection of broad-leafed plants offers them the perfect habitat.
However, goldfish prefer more open water so that they have plenty of space to swim in. Fancy goldfish and fantails are especially poor swimmers, wobbling around in the water, frequently bumping into plants and tank decorations, and even becoming trapped upside down in lush foliage.
So, having a tank that’s cluttered with too many bushy plants, bogwood, and stones can cause injury and stress to clumsy goldfish.
Also, goldfish, like all members of the carp family, love to eat plant matter. So, your beautifully planted tank will very quickly become a wasteland of torn leaves and uprooted foliage. Of course, using silk plants might help, but in reality, goldfish and bettas are simply not suited to the same environment.
What about a temporary living arrangement?
In certain circumstances, it may be possible to keep goldfish and bettas together for a short period. For example, if the filtration system in your betta tank broke, you might need to move your betta to your goldfish tank for a few days while you replace the filter.
That arrangement should be fine, although you may need to use a tank divider to keep your betta away from nippy goldfish if necessary. However, moving your betta to a quarantine tank would be a better course of action to take.
Unfortunately, there are many reasons why bettas and goldfish do not make good tankmates.
Firstly, bettas are tropical fish that need warm water, whereas goldfish are more at home in a cooler environment. The two species prefer different water conditions too, with bettas preferring softer water than goldfish. Goldfish are a rapidly growing, dirty species that produce lots of waste, and that can produce high levels of ammonia in the tank, which could make your betta sick.
Finally, goldfish grow very rapidly. Not only does that mean that you’ll need a much bigger tank than you would do otherwise, but it also increases the risk that your goldfish will eat your betta!
Bottom line: We do not recommend housing using goldfish and bettas as tankmates.