When I was a young boy, one of my first encounters with pet fish was with my neighbors who kept two goldfish.
I can vividly remember the day when they told me, remorsefully, that one of the goldfish had died, and a week later, the remaining one had died of ‘loneliness’.
Dying of loneliness. How tragic, I thought!
But did the second goldfish really die of loneliness? Many people keep goldfish alone, after all. Stick with me, as we take a closer look at whether goldfish can live alone, and whether they’d enjoy doing so.
Keeping Goldfish Alone
Many people keep goldfish alone, and many goldfish that have been kept alone have lived relatively long and healthy lives.
But that’s not to say that keeping a goldfish alone is the ideal situation! Despite common misperceptions, goldfish are intelligent fish and may be happier and healthier when given adequate stimulation.
According to Culum Brown, a fish training expert at Macquarie University, Australia, goldfish are often used as ‘learning fishes’ because of their long memory spans and ability to learn tricks!
Check out the end of this article for some amazing tricks you can teach your goldfish.
Can a Single Goldfish Survive in a Fish Bowl?
Goldfish have often been kept alone in fishbowls, but most experts today agree that this is rather a cruel way of keeping a goldfish. Kept in this way, they are often tragically short-lived.
Since fishbowls tend to be far too small, they will often stunt a goldfish’s growth. Furthermore, since fishbowls don’t usually have filters, you’ll need to change part of the water daily to keep the bowl clean and well-oxygenated.
Can Goldfish Be Kept Alone in a Pond?
While goldfish could be kept alone in a garden pond, it’d seem very sad to do so.
One of the joys of a garden pond is that they offer so much more space than an aquarium, and can host a relatively large number of fish. Goldfish kept in ponds also tend to be longer lived, and are relatively easy to breed, compared to when kept in aquariums.
Breeding goldfish in a pond can be a real pleasure, and it’d be sad to forgo this opportunity by keeping a goldfish all alone!
Are Goldfish Schooling Fish?
Strictly speaking, goldfish are not schooling fish. Schooling fish are species such as neon tetras and danios that like swimming around in tightly packed groups of the same species.
But goldfish are social fish – they appear to enjoy the company of other goldfish and will often follow each other around in a fish tank or goldfish pond.
Scientific experiments have revealed that goldfish can learn more quickly when kept with other goldfish, which indicates that perhaps these fish evolved to live together in groups.
They may also enjoy interacting with fish of other species.
Which Fish Make Good Tank Mates for Goldfish?
Although goldfish are often simply kept with other goldfish, there are some other interesting species that you can keep with them too.
But goldfish definitely aren’t a classic community tank fish! Because goldfish are messy fish and grow to large sizes, they can threaten the lives of other species either indirectly by poor quality conditions, or simply by eating them!
What’s more, goldfish are coldwater fish that won’t enjoy the high temperatures normally associated with tropical fish keeping.
Therefore, when finding tank mates for goldfish, we need to find species that are large enough, cold-hardy, and also don’t need immaculate water conditions. Let’s see…
Compatible Tank Mates for Goldfish
Snails make great tank mates for goldfish, so long as they’re large enough that the goldfish can’t fit them in its mouth!
When your goldfish is young, this will mean most types of pet snails are possible. Nerite snails are extremely beautiful and do an excellent job at keeping the tank clean from algae. They also don’t breed in freshwater, meaning you’ll never be overrun by them! But growing to only 1 inch, you may need to find larger snails for your goldfish later on!
Mystery snails and rabbit snails are two larger types of aquarium snails, growing to at least 2 inches in diameter at maturity. They are also tolerant of the less-than-perfect water conditions often present in goldfish tanks!
Variatus Platies (Platypoecilus variatus)
Variatus Platies are colorful fish that can add some interesting variety to a goldfish tank.
Unlike their tropical cousins the standard platy, the variatus platy enjoys cooler water temperatures and is happy anywhere between 61-77°F. This means they’ll do perfectly well in an unheated fish tank, in similar conditions to how goldfish are normally kept.
Because they’re livebearers, variatus platies are prolific breeders and can produce up to 100 fry with each birthing. Both the adult platies and your goldfish will normally eat most of these, although a few may survive in a densely-planted aquarium!
Danios – Danio rerio & Devario aequipinnatus
Both zebra danios and giant danios are tolerant of cooler water than most tropical fish, and so can be kept in a coldwater aquarium with a goldfish.
While zebra danios make a great choice of tank mate for smaller goldfish, they only grow up to around 2 inches long, meaning they could also become lunch for a larger goldfish!
Giant danios, on the other hand, grow up to 4 inches long and are one of the fastest and most agile fish you could hope to find. A healthy one should always be able to stay out of harm’s way!
Hognose Cory Catfish (Brochis multiradiatus)
Hognose cories are a member of the adorable cory catfish clan. Normally kept in tropical aquariums as a part of the clean-up crew, cories are fabulous for eating up leftover food and debris to prevent them from polluting the tank.
But most cories are quite small and prefer warmer water. Not Mr.Hognose! Hognose cories can grow up to a whopping 4 inches and can tolerate water temperatures down to 70°F, meaning they’re perfectly compatible with an unheated goldfish tank in a warm room.
Like other corydoras, hognose cories are schooling fish that need to be kept in groups of 6 or more to remain happy. So make sure your tank is big enough before introducing this enchanting fish!
Bristlenose Pleco (Ancistrus sp.)
Plecostomus, or plecos as they are commonly known, are one of the most popular types of algae eaters for tropical aquariums.
But while many species such as the common pleco grow to mammoth proportions (up to 12 inches long!), bristlenose plecos remain at a much more manageable 4-6 inches in length.
The good news is that bristle noses can also tolerate fairly cool water temperatures, as low as 72°F. If your goldfish tank is in a consistently warm room, you could keep these two fish together.
Alternatively, you could use an aquarium heater and set the thermostat to 72-73°F to keep both species happy.
Do note though, that plecos come from fast-flowing water that is rich in oxygen. They can only be kept in a goldfish tank if you provide them with strong filtration and a current that’s directed to the bottom of the tank where they prefer to spend most of their time.
Goldfish Tank Mates That I Don’t Recommend
There are several suggestions on the internet for goldfish tank mates that I wouldn’t endorse. One of the most common is for loach species such as hillstream loaches and dojo loaches.
These fish are specially adapted for clean, fast-flowing rivers with a very high oxygen content – exactly the opposite of what most goldfish tanks offer. Without high enough water quality, these fish are likely to die prematurely.
Rosy barbs are another common suggestion. While they can tolerate the colder water temperatures of a goldfish tank, they’re also semi-aggressive and like to nip other fish’s fins.
If your goldfish doesn’t have fancy fins, there’s a chance it could work, but I wouldn’t take the risk!
Goldfish Tank Size
If you’re thinking of keeping a goldfish with other tank mates, you need to think about your tank size first.
A single goldfish, when young, can live in a 30-gallon tank. You’ll need to add 10 gallons to that for each additional goldfish you add to the tank.
For other smaller fish, you can use the 1 gallon per inch rule. This means if you add a 5-inch long fish to the tank, you’ll need an additional 5 gallons to the tank volume to make room for it.
If you add 6 specimens of a 4-inch long fish, you’d need to multiply 6×4 to know you’d need an extra 24 gallons to house them.
Goldfish Growth Rate and Bigger Tanks
The tank size recommendations above, however, are only for young goldfish. Goldfish can grow at around 1 inch per year, meaning after 8 years, your goldfish will be around 8 inches long, and should be moved onto a larger tank.
Maximum Goldfish Size
Many people don’t realize it, but goldfish can live a long time and grow to enormous sizes! ‘Goldie’ the goldfish in the southeast UK grew to nearly 15 inches long in just as many years.
And there have been reports of goldfish growing even larger than this in home aquariums too!
Maximum Goldfish Lifespan
If you think 15 years sounds like a long time for a goldfish to live, your eyes might pop at the ages reached by some of the oldest specimens, who more than doubled this figure!
Another one from the UK, ‘Tish’ the goldfish, is in the Guinness Book of Records for being the world’s longest-lived goldfish.
Dying at 43 years old, Tish’s owner Hilda Hand attributed his long life to a very moderate feeding regime and, interestingly, occasional exposure to direct sunlight!
Keeping Your Goldfish Entertained With Tricks
Since goldfish are more intelligent than is often believed, does that mean we can teach them tricks? Absolutely!
Goldfish can learn all kinds of tricks. From the most simple ones like eating out of your hand, to some more advanced tricks like swimming through hoops.
‘Albert Einstein’, a goldfish from Pennsylvania, holds the world record for the greatest number of tricks, including doing the limbo and playing football!
So if you do decide to keep a goldfish on its own, make sure you keep it well entertained by interacting with it and stimulating its underappreciated intellect regularly!
Can a Goldfish Really Die of Loneliness?
Returning to my anecdote at the start of the article, did my neighbor’s second goldfish really die of loneliness?
Well, it’s possible. Scientists are constantly discovering how fish are more intelligent and emotionally advanced than we had previously imagined.
A goldfish with a deep bond to a tank mate could indeed become depressed and withdrawn if suddenly left alone, making serious health problems much more likely to occur.
But keeping your goldfish happy and healthy is always a combination of factors. One half is getting your water parameters, diet, and tank setup right. The other half is making sure they’re feeling stimulated and well-cared for.
Goldfish are social animals that prefer to be kept with other goldfish, or at least with some other fish species. Living with other fish helps to keep your goldfish active and healthy, and lessens the chances of stress and depression.
If you do decide to keep a goldfish on its own, make sure you take extra-special care of it to keep it feeling stimulated and well-cared for.