koi fish

Goldfish vs Koi Fish: Which One Is Better?

With so many people choosing goldfish as a pet, there’s bound to be some confusion when it comes to what really distinguishes koi fish from goldfish. After all, they’re both found in the same section of the pet store. While goldfish are great pets to keep, there is also much more to koi fish than meets the eye. In this article, I will discuss some similarities and differences between goldfish and koi fish.

Goldfish Vs Koi Fish

Here are a few differences between goldfish and koi fish:

1- Origin

koi fish

The origin of the koi fish is Japan. It was originally bred as a food source, with the first koi caught in Lake Biwa in Nara Prefecture. The type of koi that was caught was known as Nishikigoi, which were brown and white-colored.

In Japan, during the early times, it was common for people to keep these fish as pets. They were kept in ponds or lakes and fed on scraps from households or on grains that were thrown into the water by farmers.

Goldfish originated from China. They are also known as Chinese Carp or Japanese Carp and are considered a delicacy in China. The color patterns of these fish vary from place to country but they all have one thing in common: they have red eyes!

2- Temperament

Goldfish are generally peaceful and active fish, though they will sometimes fight with other goldfish and other species of similar size. Koi, on the other hand, are known for their aggressive behavior toward each other, especially when females are spawning and protecting their young.

3- Color


Koi have a more vibrant coloration than goldfish do. They have dark bodies with vivid reds, blues, oranges, or yellows on their scales. Koi also have metallic highlights in their scales which make them look even more attractive. In contrast, goldfish have duller colors that range from white to orange to red. The only real difference here is the fact that koi are more colorful than goldfish.

4- Size

Another difference between these two types of fish is their size. A koi can grow up to 18 inches long while a common goldfish only grows up to 6 inches long at most (usually they’re smaller). The largest koi can weigh up to 30 pounds while the largest common goldfish weighs around 1 pound at most. So if you want an animal with impressive size then go with a koi rather than a goldfish!

5- Fins

Koi fish have long, flowing fins and a more rounded shape than the fins of goldfish. The tail fin on a koi is normally forked, and the body is colored red, orange, or white. Koi are bred to be ornamental fish, rather than eaten. They can grow to be quite large, with some specimens reaching weights of over 20 pounds.

Goldfish have one dorsal fin placed near the rear of their bodies. These fish have large scales, which are small compared to those of koi. Their bodies are rounder than koi and they have smaller eyes and mouths. They come in a variety of colors including orange, yellow and white with black spots. Goldfish are known as domesticated carp that have been bred for food as well as pets for thousands of years.

6- Lifespan

The lifespan of a koi fish is about 20 years, while the average goldfish has a lifespan of 10 to 15 years.

7- Diet

Goldfish have a preference for protein-rich foods, such as live or frozen brine shrimp, bloodworms, and tubifex worms. In addition to these live foods, goldfish also require a high-protein pellet designed for omnivorous fish. Many hobbyists supplement their goldfish’s diet with algae wafers. If you do choose to feed your fish wafers, be sure to remove any uneaten portions within 24 hours so that the algae doesn’t start to decompose and release toxic substances into the water.

Koi also require a high-protein diet of meaty foods like mosquito larvae and brine shrimp supplemented by vegetable matter like lettuce or spinach. You can also feed your koi commercial pellets designed for carnivorous fish.

8- Tank Requirements


Goldfish do not need a large aquarium to live a happy life. A tank that is 20 gallons (76 liters) or more is recommended for one fish and 10 gallons (38 liters) or more for two fish. The larger the aquarium, the happier your goldfish will be.

Goldfish like to be kept in warmer water temperatures between 72°F (22°C) and 82°F (28°C). The temperature should be uniform throughout the tank so that each end does not have different temperatures than the center of the tank. To make sure this happens, you may need an external heater if your home does not provide enough heat naturally or an aquarium chiller if it does not provide enough cooling for your goldfish’s comfort level.

Koi need lots of room in their tanks because they grow so large. The minimum size recommended for one adult koi is 20 gallons per inch of body length, so a 3-inch koi would need at least 60 gallons of water. For two or three large koi, you’ll need significantly more space than this minimum requirement. You should also provide plenty of hiding places for your fish — both in the tank itself as well as submerged rocks and plants — since they like to hide from view every once in a while.

You want to keep your water temperature between 70-85 degrees Fahrenheit (21-29 degrees Celsius). If you live in a warmer climate, then this shouldn’t be hard to do. However, if you live in an area where the temperature drops below freezing during the winter months, then you will have a more difficult time maintaining this temperature in your tank.

9- Compatible Plants

Koi can be kept in a variety of tanks, but they do best in large ponds. If you have a pond and want to keep koi fish, there are some plants that work well with them.

  • Duckweed
  • Water Lettuce
  • Water Hyacinth
  • Amazon Frogbit

Similarly, the following plants do well in goldfish tanks:

  • Java Moss
  • Water Sprite
  • Anacharis
  • Anubias
  • Dwarf Water Lilies

10- Cost

The average price of goldfish is $3-$20 per fish, depending on the size and whether or not they have been dyed. A large aquarium with filtration and lighting could cost anywhere from $100-$300 or more for an established tank with plants and decorations included.

The price of Koi also greatly depends on their size, color, quality, and rarity. Most common species of Koi fish sell for between $10 and $50 each, but rarer varieties can cost hundreds or even thousands of dollars each.

11- Diseases

Here are 5 of the most common koi fish diseases:

  1. Ichthyophthirius multifilis (Ich)
  2. Columnaris (Cotton Wool Disease)
  3. Trichodina & Costia
  4. Velvet, Costia & Trichodina
  5. Bacterial Infections

Similarly, goldfish are also prone to diseases. Here are some common goldfish diseases.

  1. Fin Rot
  2. Swim Bladder Disease
  3. Dropsy
  4. Ichthyophoniasis
  5. Cyprinid Herpes Virus (CHV)

Frequently Asked Questions (FAQs)

Which Is Better Koi Or Goldfish?

If you have a pond then Koi are better than goldfish but if you are an aquarium owner then goldfish are better because of their appearance.

Can You Keep Koi With Goldfish?

 Koi are a type of carp and goldfish are carp. So yes, you can keep koi with goldfish.


When it comes to the world of fish, goldfish and koi are certainly two of the more popular options. Both have a long history with humanity and have grown in popularity over time. However, despite sharing a good deal of similarities, both goldfish and koi fish also have their own unique quirks. Which one is better? It depends on what kind of tank step-up you have, but hopefully, this article will give you a starting point towards finding an answer.