Eggfish Goldfish: Defining Features, Care Needs and More

Close up side view of an eggfish
By Michelle Jo (Own work) [CC0], via Wikimedia Commons
Among the rarest of all goldfish varieties out there, eggfish are hard to find even in their native China but are prized among collectors.

Anyone interested in keeping these fish will likely have to seek out specialist breeders since you’re probably not going to stumble across an eggfish when visiting your local pet store.

We’ve got the lowdown on these elusive fish, so read on if you want to know more.

Eggfish Characteristics

They were (likely) given this name because of their compact egg-shaped bodies. They lack dorsal fins, which further contributes to their egg-like appearance.

This also means they have smooth arched backs, uninterrupted by the dorsal fin, the highest point being right in the center of the backbone A traditional eggfish has a short double tail, whereas a phoenix type has long flowing fins.

Do They Come in Different Colors?

They can be found in a wide range of colors and all scale types – matte, nacreous, and metallic.

One of the rarest and most sought-after variations is the blue phoenix eggfish – or blue egg phoenix, as it’s sometimes called.

As mentioned above, the Phoenix variety have long flowing tails and, as the name suggests, blue phoenix are blue in color.

Size of Eggfish When Fully Grown?

On average, they reach about 5 to 6 inches in length, but they may occasionally grow up to an inch or so larger.

How Old Can They Get?

The average lifespan of an eggfish is around 15 years if well looked after.

Of course, many goldfish live significantly shorter lives than this, but it’s usually due to improper care. So, as long as you look after them properly, they may be with you for well over a decade.

From Where did They Develop?

They were originally developed in China, which is where all goldfish can be traced back to.

There’s not a large amount of information on the specific origins of them, but — according to the Goldfish Society of America — they were among the earlier types of goldfish developed.

While their origins are likely to date back well over 800 years, the first recorded mention of them wasn’t until 1726 in the book ‘The Chapter of Fowls and Insects, Collection and Contemporary Books with Illustrations’ by Jiang Ting Xi.

Today, they are so rare that the Goldfish Pagoda in Hong Kong has dedicated resources to breeding blue phoenix eggfish, and even sent 18 specimens to the United States in the mid-90s, to help with the repopulation efforts.

However, since they’re slow spawners, breeding them isn’t the most straightforward process.

Are they Easy to Keep as Pets?

They are no easier or harder to keep in a home aquarium than an average fancy goldfish, which means they are relatively easy and suitable for even beginner hobbyists willing to do a little research and cater to their basic needs.

Eggfish Care Considerations

Beyond the regular care requirements of any goldfish, they don’t have any particular needs you have to consider.

What Food do They Need?

Eggfish are omnivores and thrive on a varied diet. While their diet should include a high-quality commercial flake or pellet food specially designed for goldfish, this shouldn’t be the only thing they eat.

You should also feed them a range of plant-based and animal-based foods, including brine shrimp, shelled peas, zucchini, blueberries, mosquito larvae, and bloodworms.

These may be fresh, frozen, or freeze-dried.

It should go without saying, but ensure any foods are cut to an appropriate size for your fish. These supplementary foods don’t need to be fed with every meal, but giving them to your fish at least a few times a week will improve their health and nutrition.

They don’t have stomachs, so they do better eating little and often. Instead of feeding your eggfish one large meal a day, try to offer two or three smaller meals.

Tank Requirements

They have a few specific requirements when it comes to proper aquarium set-up in order to stay happy and healthy. Let’s take a look at the details now.

Recommended Tank Size and Shape

Although they aren’t huge, they need surprisingly large tanks. Like all goldfish, they produce a lot of waste, and the larger the tank, the less of an issue this will be.

It’s also worth considering that your fish’s aquarium is essentially their whole world, so it’s kinder to provide them with as large a tank as you can.

The minimum aquarium size you should aim for is 30 gallons for an individual, plus an additional 10 gallons for every other fish. So, if you were to keep five, for example, you’d need a 70-gallon tank.

Rectangular/cuboid tanks that are wider than they are tall are ideal. This gives the water inside a larger surface area, which increases the oxygen content, and gives them a wider lateral swim space.

Do their Tanks Need Filtration?

Like any goldfish, they absolutely need a filter in their aquarium. Some newbies to the fish keeping world assume goldfish are fine without filtration, but this couldn’t be further from the truth.

As mentioned above, they produce a lot of waste, and so they need a high-quality filter for their aquarium. Otherwise, you’d need to change the H2O in their tank daily to keep reasonable water quality.

Choose whatever type of filter you prefer (we recommend canister filters mostly), but make sure it’s adequate for the size of your tank.

What Substrate Should you Add?

Substrate isn’t a must-have, but goldfish do like to forage for food in their tank’s substrate so that it can give them some extra enrichment in their life. Besides, some aquarists just prefer the look of substrate.

If you do choose to use a substrate, choose either fine sand, large gravel or rocks that are too large for your eggfish to swallow. Some goldfish have a tendency to eat smaller gravel, and it can get stuck in the digestive tract, causing major issues.

Should you add Lights to the Tank?

They don’t necessarily need artificial lighting if in a room with plenty of natural light, though it’s worth noting here you should never keep an aquarium in direct sunlight.

That said, most people do light their goldfish’s tanks, as they generally look more attractive that way.

If you light your goldfish’s tank, be sure to follow a natural day/night pattern of about 12 to 16 hours of light, followed by about 8 to 12 hours of light, and so on. You may want to set your lights to a timer to keep the cycle regular.

Water Temperature

Their ideal water temperature is between 65 and 72 degrees Fahrenheit.

Compatibility With Other Fish

Since they are so rare, there’s not a lot of information available regarding the best tank mates for these goldfish. To be on the safe side, we’d ideally recommend housing them with other eggfish only, or other slow swimming fany types of goldfish that will not outcompete them for food or bully them in any way.

They should be relatively strong swimmers, despite their absent dorsal fin, so they could be fine in a tank with other fancy goldfish, but you’d have to keep a close eye on them to ensure they’re getting enough food.

Video: A Close Look at the Eggfish in Action

The following video shows a pair of blue phoenix eggfish in action.


Final Thoughts

While eggfish aren’t easy to get hold of, their rarity alone makes them somewhat more desirable and they can certainly make an excellent addition to your home aquarium. They aren’t hard to care for, live a long life, and are curious little creatures that are fun to watch and be custodian of.

If you’re interested in keeping eggfish, do your research and look for a reputable breeder who’s doing their bit to further this declining goldfish variety, and enjoy being a part of keeping their breed alive.

Happy fish keeping!

Wendy Kathryn

Hi, I'm Wendy, the owner and creator of this website, an experienced fish keeper and avid student of the art since 2010. My aim is to help beginners avoid the many possible mistakes when getting started in this wonderful hobby.

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