Bettas and goldfish are two of the most popular fish species kept as pets, so it would be great to have both species swimming around together in your home aquarium, right? But, can bettas live with goldfish? Bettas are known for their aggression toward other fish. So, would your two pets fight, and will betta fish eat goldfish?
Keep reading to find out why keeping these two iconic fish species together is perhaps not the best move!
Betta Fish and Goldfish
When it comes to choosing pets for kids, goldfish and bettas are right up there at the top of the list. Without a doubt, they’re both beautiful, hardy fishes, but that’s where the similarity between them ends.
Betta fish are members of the Osphronemidae family of tropical fishes that come from southeast Asia. There are 73 varieties of betta fish, most of which are captive-bred and heavily hybridized to create the spectacular finnage and colors that fish keepers love.
There are wild populations of bettas, mainly in the Mekong and Chao Phraya river basins in Thailand, where the fish inhabit shallow, slow-moving water, such as marshes, rice paddies, and floodplains. Bettas are labyrinth breathers, meaning that they have a specially developed breathing organ that enables the fish to take gulps of air at the water surface.
That evolutionary quirk allows the fish to survive in oxygen-depleted water during the dry season. Unfortunately, that has led to the belief that betta fish can be kept in tiny vases or bowls with no proper filtration, which is absolutely not the case. According to studies carried out by Adelphi University, bettas need a tank of at least two gallons with an efficient filter system, lighting, and heating.
The goldfish that you see for sale in pet stores around the world are descended from a species of wild Prussian carp that are native to Central Asia. There are thought to be around 125 species of goldfish, all of which have been produced through intensive hybridization and captive breeding. Unlike bettas, there are no officially recognized wild goldfish.
Like bettas, the wild carp from which modern goldfish are descended live in the slow-moving water of lakes, ponds, ditches, and rivers. And, like many captive bettas, pet goldfish are often subjected to life in a small bowl or tank with no filtration system. That’s a disaster for the goldfish, as these are very dirty fishes that produce a lot of waste, so an efficient filter is essential.
Betta Fish Aggression
Betta fish are also known as Siamese Fighting Fish and for a good reason!
Male bettas are highly territorial, and they will defend their patch to the death if necessary. Around 700 years ago, indigenous Thai people recognized that behavior and kept and bred wild bettas for fighting. The owners of these “Plakats” and spectators would bet on the outcome of the fights. In fact, in the 1800s, the King of Siam licensed betta fights and was an owner of fighting fish himself.
Goldfish, on the other hand, are pretty chilled-out creatures, and they grow a whole lot bigger than bettas too. However, goldfish have a reputation as fin-nippers, and your betta fish’s beautiful, flowing finnage would almost certainly be a prime target for your goldfish.
So, if you place a confirmed fin-nipper in the same environment as an aggressive, territorial fish that views any brightly colored creature with trailing finnage as a potential threat, you’re inviting carnage in your aquarium! See our recommended tank mates for betta fish here.
Cleanliness and Filtration
Goldfish are large, extremely dirty fish that produce huge quantities of waste. That’s because a goldfish doesn’t have a stomach, so all the food it eats passes right through the fish and out into the tank. To control the pollution they create, your goldfish tank must have a mature biological filter system to manage the Nitrogen Cycle; otherwise, the levels of ammonia and nitrites in the water will quickly rise to toxic levels.
Unfortunately, even though betta fish are pretty hardy critters, they are highly sensitive to ammonia spikes and can easily succumb to ammonia poisoning, which often proves fatal.
Also, a tank containing goldfish requires frequent partial water changes to keep the water clean and hygienic. That’s fine for goldfish, but bettas get stressed by too frequent water changes, which can compromise their immune system and leave them susceptible to disease and attack by parasites.
As mentioned above, a goldfish tank needs a pretty powerful filtration system to keep the tank water healthy for your fish. That means a fairly strong water flow through the aquarium, and that won’t suit your betta at all. Bettas are very small fish compared with goldfish, and they aren’t strong swimmers, preferring a low to zero current. When I kept a betta fish, the filter system in his tank had a baffle fitted to restrict the current whilst maintaining the flow. Alternatively, a gently bubbling sponge filter would work well in a betta tank.
In contrast, goldfish like to have reasonably strong water flow in their environment. Even my fantails enjoy playing around in the bubbles and current that my filter system generates in their tank. Also, a sponge filter system won’t be sufficient to cope with the amount of waste that goldfish produce.
Bettas are tropical fish that need warm water if they are to thrive. The preferred temperature range for betta fish is between 75o and 86o Fahrenheit. If the aquarium temperature drops below 75o, your betta may suffer temperature shock, or at the very least, his metabolism will slow down. When that happens, your fish will become listless, he’ll stop eating, and his compromised blood circulation may lead to diseases such as fin rot.
Goldfish, on the other hand, are classed at coldwater fish, happily living in water temperatures between around 68o and 74o Fahrenheit. Goldfish can also suffer from temperature shock but when the water is too warm, rather than too cold.
So, you can see that goldfish and bettas are not at all compatible when it comes to their preferred water temperatures.
Goldfish grow considerably larger than bettas. So, although a 10-gallon tank would be fine for a betta, that would be far too small for a goldfish once the fish reached maturity.
Tank décor is another area where goldfish and bettas have very different likes and dislikes. Betta fish favor a heavily planted aquarium with lots of hideouts and resting places. Goldfish prefer open water with lots of swimming space. If you have fantails or fancy goldfish, they’re very poor swimmers. Mine spend much of their time wobbling around the tank, bumping into things or rummaging in the substrate, uprooting and destroying plants.
So, too much planting, driftwood, and rocks might be perfect for a betta, but they present a very real hazard to goldfish.
Fish extract the minerals that they need from the water, and they have different tolerances to water hardness.
Bettas like soft water with little or no calcium content (kH). The lower the calcium levels in the water, the lower the pH level will be, and betta fish need a pH of around 7.0 to thrive. However, goldfish prefer water that has a higher pH level in the range of 7.2 to 7.6, which has a higher calcium content.
Can You Keep Bettas And Goldfish Together Temporarily?
In an emergency, for example, if your betta tank filtration system failed, theoretically, you could put your betta in your goldfish tank for a day or so while you replace the filter unit. However, it would be a better move to temporarily house your betta in a quarantine tank if you have one.
So, can your betta live with your pet goldfish? Unfortunately, there are lots of reasons why goldfish and betta fish don’t make suitable tankmates.
Bettas are tropical fish that live in warm water, while goldfish are cold-water fish. Bettas prefer soft water, whereas goldfish need water with a higher pH and more calcium content. Goldfish are very dirty fish that generate a high volume of waste that could cause an ammonia spike in the tank, which would be dangerous to your betta.
The bottom line: although you could get away with putting a betta fish with a goldfish in a case of emergency, these two beauties are not in any way compatible to live together in the long-term.
I hope you enjoyed this article. If you have any questions, please enter them in the comments box below.