Through many years of attempting to keep different fish together, I’ve discovered that there are some that just don’t work.
Betta fish and goldfish are not ideal tank mates for each other, for a variety of reasons. Betta fish can be extremely aggressive towards goldfish as they are very territorial. Goldfish and betta fish also have vastly different water temperature requirements.
Keep reading to find out everything there is to know about keeping these two fish together and why it is generally considered a bad idea.
Can Betta Fish Live with Goldfish?
The unfortunate reality is that betta fish and goldfish do not make for good tank mates, and it all starts out with the water temperature.
Goldfish are cool water fish, and they prefer the water temperature to be anywhere between 60.8 and 71.6 degrees Fahrenheit, or between 16 and 22 degrees Celsius.
On the other hand, we have the betta fish, which requires a water temperature of around 75 to 80 degrees Fahrenheit, which is approximately 23 to 27 degrees Celsius.
Besides betta fish being extremely aggressive and territorial, the water temperature is perhaps the biggest reason as to why these two fish cannot be kept together.
Goldfish do not do well when the water gets too warm, as it can cause issues with their metabolism, digestion, immune system, and more. Goldfish that are kept in waters that are far too warm can start to suffer from heat stress, general stress, and may start to develop disease and other health conditions.
Really, the same thing can be said for betta fish that are kept in conditions that are far too cold. If a betta fish is kept in cold water, its metabolism is going to slow down, its immunity will weaken, it will become lethargic, eat less, and also be in general poor health.
Both goldfish that are kept in excessively warm waters and betta fish that are kept in excessively cool waters can eventually die due to temperature stress.
Another reason why it might not be ideal to keep goldfish and betta fish in the same tank is due to simple spatial requirements. Betta fish are generally happy in tanks of around 5 or 6 gallons in size, but the same cannot be said for goldfish.
Your average goldfish may need a tank anywhere between 30 gallons and 50 gallons in size (or more), depending on how large the goldfish itself is. As you can see, goldfish require much more space to be happy than betta fish.
Sure, you might be able to get away with putting a small betta fish inside a very large goldfish tank, but putting a relatively large goldfish into a very small betta fish tank will not work.
Goldfish do not do well in very cramped conditions and may start suffering from stress and other health related issues due to being kept in cramped conditions. Goldfish just need much more space and they won’t be happy in a small betta fish tank, which actually brings us to our next point, bioload and tank conditions.
Another reason why it is not a good idea to keep betta fish together with goldfish is due to the bioload in the tank. First, we have the betta fish, which is actually a relatively clean fish that does not produce much of a bio load.
Although the tank for a betta fish does require a bit of filtration, you don’t need all that much. However, the story is very different for a goldfish. Goldfish are considered to be somewhat dirty fish, or in other words, they produce a lot of bioload.
In simplest terms, goldfish eat a lot of food, they leave a lot of uneaten food behind, and they produce a lot of waste or fecal matter as well. Goldfish tanks require extremely good filtration to keep that water clean, or else poor tank conditions will develop very quickly.
Ammonia levels, nitrite levels, algae blooms, and more are all common in goldfish tanks that do not have good filtration. With that being said, with all of the filtration that is required for a goldfish tank, the flow rate of a goldfish filter may be a little too high for a betta fish.
What also needs to be considered here is that betta fish are some of the most temperamental, territorial, and aggressive fish around. They generally do not like being kept with other fish, particularly other males. This is no more so the case than when other fish somewhat look like a betta fish.
Now, take into consideration that fancy goldfish, and even regular goldfish, can have relatively have long fins and somewhat resemble betta fish. It is not uncommon for a male betta fish to mistake another goldfish for a different betta fish.
This often results in extreme aggression, bullying, and territoriality. It would not be the first time that a betta fish bullied and harassed a goldfish mercilessly to the point of extreme injury or even death.
Although a betta fish may not be larger than your average goldfish, they will still bully them and attempt to kill them. This is perhaps the biggest reason as to why keeping these two types of fish together is not a good idea.
Interestingly enough, no matter what type of goldfish and Betta fish you have, they should not be kept together. Although, why they should be kept together can differ depending on the size of the goldfish. We already mentioned above how a male betta fish may mistake a goldfish for another betta fish, which often results in aggression and bullying.
This is the case if the goldfish isn’t too large and is of a similar size to other betta fish. However, as you might know, some goldfish can get very large, up to a foot in length, and in many cases even larger, which is true even in home aquariums.
Goldfish are fairly voracious eaters and quite indiscriminate as well, which means that they’ll eat mostly anything that they can fit their mouths around. If a small betta fish is unlucky enough to be caught by a goldfish, it will surely become a snack. It is not uncommon for very large goldfish to eat other smaller fish in their tanks, and yes, this includes the betta fish.
Best Tank Mates for Betta Fish
Seeing as the goldfish is not the best tank mate for the betta fish, you might be wondering what is. Well, a variety of suckermouth fish and bottom feeders are ideal to keep with betta fish, as they generally are not seen as threats.
Smaller fish like tetras and guppies may also make for good betta fish tank mates. Other good betta fish tank mates include shrimp, crabs, snails, and even frogs. Really anything that can’t get mistaken for another betta fish by a male betta fish makes for a good tank mate.
Best Tank Mates for Goldfish
Seeing as the betta fish is not the best tank made for the goldfish, you might now be wondering what is. Generally speaking, most fish that can’t fit inside of a goldfish’s mouth are ideal tank mates, because they can’t be eaten. A wide variety of zebrafish, sucker mouth catfish, rasboras, loaches, catfish, platies, barbs, and other such fish all make for decent options.
Keeping Betta Fish and Goldfish – Final Thoughts
The simple reality is that keeping betta fish and goldfish together is not a good idea. Betta fish are far too aggressive and territorial, and will often attack smaller goldfish. On the other hand, large goldfish will often try eating smaller betta fish, as long as they can catch them.
Goldfish and betta fish then also have fairly different tank requirements, including different spatial requirements and temperature requirements. What it all comes down to is that these are two things that you really just don’t want to keep together, or else you’ll keep running into problems.