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Common Goldfish: Top 5 Care Tips (+ Tank Mates, Size, Lifespan)

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By Lindsey Stanton

common goldfish

Hey, I’ve got some exciting news: Want to know why the Common is possibly the BEST breed of goldfish you can get? That’s right: The humble, “plain Jane” Common goldfish is far more special than you would have thought. And they can actually make the best pet fish of all time. Why? Keep reading to find out!

Breed Profile and Summarized Care Tips

Common name(s):Common goldfish
Scientific Name(s):Carassius auratus
Care Level:Easy to Intermediate
Temperament:Peaceful and social
Adult Size:10 to 12 inches (and occasionally more!)
Color Form:Various solid, bicolor and combinations of red, orange, yellow, white, black. Mostly metallic orange or orange and white.
Lifespan:10 to 15 years. 20 years+ is not unheard of.
Minimum Tank Size:40 gallons, bigger is better, prefer to be in a pond.
Typical Tank Setup:Strong and efficient filtration, preferably planted, sand or gravel substrate to dig into, with good lateral swim space, so preferably wide tank, rather than tall.
Tank Level:All over
Water Conditions:Freshwater, 65-75 degress fahrenheit, KH 4 to 20, pH 6 to 8
Tank mates / Compatibility:Other single-tail goldfish, invertebrates, koi, minnows, african dwarf frog, other 'pond species.'

Reasons to Love the Common Goldfish

1. Common Goldfish are Tough as Nails

cat pawing at fish
Image Credit: Maleo, Shutterstock

Look: Many goldfish are the delicate fancy kind with a predisposition to problems. Sure, they’re drop-dead gorgeous. BUT… These don’t usually live beyond 5-10 years due to all the inbreeding. And they are often plagued with chronic swim bladder problems (which can lead to early death). Every little thing has to be just so or problems can arise.

Not so with Mr. Common! Maybe he won’t win any beauty pageants. But he is like a good friend. Forgiving of your mistakes, flexible and easy to please. Of course: That’s not to say he’s un-killable. He isn’t made of steel. But if any fish were to survive, it would be HIM!

In fact, I think it’s safe to say that no domesticated fish on planet earth is tougher than the humble Common. They’ve been known to outlast marginal water conditions, frigid winter water temperatures, missing meals during vacation. Several are even known to survive after jumping out of the tank—one for as long as 7 hours!

2. Commons Make Great Pond Fish

goldfish eating in pond
Image Credit: Andrea Geiss, Shutterstock

These guys are even hardy enough (many times) to survive in an unfiltered bowl for years on end. Perhaps this is why they make such great pond fish. Agile enough to evade predators—and hardy enough to take months of cold and no food.

So, what is the secret to the Common goldfish’s ability to surpass all other fish for resilience and strength? It lies in being the most like it’s ancestor —the carp. The difference is mostly in color. The mud-colored carp has been selectively bred to have a rainbow of vibrant colors and patterns, giving us what we call goldfish. But these colors are less desirable for a wild fish that doesn’t want to be noticed by predators. The bright colors are memorizing, while the fish retain their natural survival mechanisms.

Nice thing: Even in spacious ponds, these fish don’t get nearly as large as Koi, so they are a popular choice for smaller ponds.

3. Commons Live for a Long Time

woman playing with pet goldfish
Image Credit: iordani, Shutterstock

Clearly winners of the goldfish longevity race—of the world’s oldest goldfish: The MAJORITY were Commons. Perhaps thanks to their being super tough, they are also the most long-lived. If you want to have a pet that can stick around for a long time, the Common is a good way to go.

Now, I can hear some of you saying “Then why do most of those fair/feeder fish die so quickly?” Well, in my opinion—it’s not really the fish’s fault. The conditions these fish were kept in first contribute to the spread of disease. It’s hard to find one that doesn’t come without some parasite. But when you do… … You can expect to have it around for a while with the right care

4. Commons Can Regulate Their Growth

goldfish in bowl
Image Credit: DJ Srki, Shutterstock

You heard it right: These fish are much smarter than people give them credit. In this respect, they aren’t superior to other kinds of goldfish, as all goldfish can do this. But since they get such a bad rap for growing too big for the average owner and requiring lots of space, I figured I’d throw this one in there.

Get this: Since they produce a growth inhibiting hormone (GIH) when kept in smaller spaces without lots of large water changes. They can limit their size from 12″+ (potential size) to around 4″ (stunted size). (Provided they start off as young, small fish – there’s no reversing growth) And contrary to online rumors? There is no evidence that this is harmful to their long-term health or longevity. Pretty neat, huh? Read More: Stunted Growth

If you're a new or experienced goldfish owner who’s unsure of the best housing setup for your goldfish family, check out our book, The Truth About Goldfish, on Amazon.

The Truth About Goldfish New Edition

It covers everything about ideal tank setup, tank size, gravel, aquarium ornaments, and so much more!

5. Commons Get Along Well with Others

common goldfish
Image Credit: vu dinh quoc an, Shutterstock

Commons are friendly, spunky, cheerful companions who aren’t demanding. And they have a peaceful nature. They’ve been known to be kept in tanks for years with tropical fish, due to their fast swimming to help them evade “pickers.” They can also adjust to a huge variety of water temperatures and conditions.

And if you’ve ever seen a group of commons together, you’ve probably noticed how well they get along (well, except during breeding season that is!). Really, the biggest problem seems to be if the goldfish is big enough to fit another fish in it’s mouth. In that case, it’s usually game over.

Common Goldfish Breed Description

This breed of goldfish is also dubbed by experts as the “Hibuna.” I kind of prefer that name. These are the ones you see at the fair with the shorter tail fins. They have a long slender body. Very similar to the Comet goldfish, but they lack the long tail and long fins. Arguably, an advantage. See: The long tail is more attractive to the eyes of most people.

But it continues to grow as the fish ages. If it grows a lot it can sometimes become a bit of a nuisance – dragging on objects in the tank can cause irritation, tears and other damage to the fins. Now: The short fins of the common actually give the fish more swimming control, allowing them to maneuver backward and sideways more easily. And if you’ve ever seen one of them in action. You know they are FAST! If there was such a thing as goldfish racing these guys would be the winners for sure. (Try catching one with your bare hands and you’ll know what I’m talking about!)


Commons are mostly found in orange, but there are other more unusual color patterns.

Color Patterns
  • White
  • Yellow (rare)
  • Red/white
  • Black/red
  • Yellow/black
  • And more.

Brown is usually a juvenile color and can be considered a “mystery fish” that will change. Not too many breeders are out there breeding these, so you probably won’t find as much variety as with other types.


Common goldfish CAN reach a length of 12″ or more when given access to lots of fresh water. But they don’t have to. As discussed above, these fish have the ability to limit their growth under certain environmental conditions, some only reaching 4″ or so.


Common goldfish can stand temperatures all the way down to near freezing in the winter to low 90’s in the summer. They are not picky and can adapt well to most temperatures, provided they are adjusted gradually. Caution must be taken when coming out of winter though, due to bacteria multiplying in the water before the fish’s immune system is competent.


The best food for these fish is a staple diet of pellets, flakes or live foods. They also should have access to grazing roughage in the form of plant material. Lettuce, spinach, kale etc. all make good grazing to keep their digestive tract moving. Read More: Best Diet for Goldfish

Tank Mates

As mentioned, Commons do quite well with many other kinds of fish. They cohabitate with other coldwater fish and even with many tropical species. Koi and Commons are a popular combination for ponds.


As a free prize won at a fair or a rescue for 35 cents, these fish are a popular choice for smaller aquaria, including bowls and nano fish tank starter kits. With clean water and not overfeeding, they can do quite well in these for many years. With the use of carbon cartridges in filters and a more frequent water change schedule, these fish may outgrow the smaller tanks and require upgrades to something such as a 40-gallon fish tank or even a pond. Read More: Tank Size


These fish are PROLIFIC breeders when kept in ponds outdoors. Perhaps that is why they are such popular “feeder fish,” sold as reptile food at pet stores. Indoors, breeding them is much the same as breeding other goldfish. You can read more about that in this post: Related Post: How to Breed Goldfish

aquarium plant divider


I hope you learned something new about this underrated pet. Want to share your thoughts? Do you have an amazing pet Common goldfish? Leave your comment below—I’d love to hear it!

Read More: 5 Basics of Nano Goldfish Keeping

Featured Image Credit: Heidi Schneider, Shutterstock


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