One of the stranger types of all fancy goldfish, the bubble eye is quite hard to get hold of unless you go to a breeder, since they’re known to be delicate and reasonably hard to look after properly.
If you’re dedicated to the cause, however, and think you can provide a healthy and happy home to a bubble eye goldfish, they’re a unique-looking fish that can be rather enjoyable to watch in their tank.
In this guide, we take a detailed look at the bubble eye goldfish. We dive into their particular care needs, tank setup, preferred environment, tank mate compatibility and more.
Read on for our full guide where we start with a summarized table of all important facts and figures.
Contents - Click to Jump to Section
Profile, Care Overview and Statistics
|Common name(s):||Bubble eye, water bubble eye,|
|Scientific Name(s):||Carassius auratus|
|Temperament:||Peaceful and social|
|Adult Size:||5 to 8 Inches|
|Color Form:||Solid or mix of red, orange and black, and calico|
|Lifespan:||10 to 15 years commonly, 25 if expertly cared for|
|Minimum Tank Size:||30 gallons|
|Typical Tank Setup:||Absolutely nothing sharp becasue eye sacs pierce easily. Good filtration, but baffled intake to prevent sac being sucked in. Soft live plants, and rounded substarte to dig in enjoyed|
|Tank Level:||All over|
|Water Conditions:||Freshwater, 65-75 degress fahrenheit, KH 4 to 20, pH 6.5 to 7.5|
|Tank mates / Compatibility:||Not recommended for community tanks (eye sacs too sensitive, and poor swimmers), except for good with own kind and celestial eye goldfish.|
The bubble eye goldfish is an egg-shaped fancy type with a double tail and no dorsal fin. Due to their lack of dorsal fin, there should be a smooth arch from their head to their tail.
Their most striking feature, however, is the large fluid-filled sacs that develop just below their eyes.
These “bubbles” start to grow at around 6 to 9 months of age and reach their full size at roughly two years. These sacs cause their eyes to upturn slightly, but not nearly as dramatically as those of the celestial eye goldfish.
Do They Come In Different Colors?
They come in a range of colors, including red, orange, blue, black, calico, and bi-colored (either red and white or red and black).
A notable variation of is one variety only commonly bred in China which does have a dorsal fin.
What Size is a Fully Grown Adult?
The average size of a bubble eye goldfish is around 5 to 6 inches long.
However, some people have reported their bubble eyes growing significantly larger — even up to 8 inches long — when kept in the correct conditions.
How Long can Bubble Eye Goldfish Live?
They have an average lifespan of about 10 to 15 years when properly cared for, and they can live for even longer.
However, the sad fact is, many people keep them without ever learning the correct way to look after them, which is why many live for a significantly shorter amount of time.
History and Development
Not a great deal is known about the specifics of their origins, but — like all goldfish — it descends from a type of carp that was kept in ornamental ponds in China.
We can tell from their appearance they are a product of extensive selective breeding. It’s believed these fish were first developed in the 1900s in China, probably from a variety of celestial eye, but we don’t know any more details than that.
Are they Hard to Care for?
They are considered one of the hardest varieties of goldfish to keep in a home aquarium.
They’re physically delicate due to their unique anatomy, and they’re unlikely to thrive if placed in an established tank or if their owner gives little thought to their unique needs.
Any Special Care Considerations?
Typical goldfish care needs aside, providing a safe environment for them is important. Their delicate eye sacs can rupture if caught on a sharp or protruding object, so avoid adding any sharp or rough ornaments or gravel to their tank.
Provide cover with either completely smooth ceramic ornaments or with silk or live plants — even sharp edges on plastic plants are potentially dangerous. While their eye bubbles will sometimes grow back, an injury would be painful, and there’s a chance of catching a life-threatening infection.
The other main thing to consider is their poor swimming abilities. When selecting a filter, ensure it doesn’t create too strong a current in the water, since these fish can move around much better in still water.
What Should You Feed Them?
Bubble eyes have similar dietary requirements to all goldfish.
The thing to remember is they’re omnivorous. This means they can eat plant foods and animal foods, and thrive on a varied diet. We’d recommend starting out with a high-quality flake or pellet food designed specifically for fancy goldfish.
To keep their diet more interesting, and the provide additional nutrition, occasionally supplement this with fresh, frozen, or freeze-dried foods such as shelled peas, bloodworms, or mosquito larvae.
Since they don’t have stomachs, they’re easy to overfeed and can suffer from a range of digestive issues if you feed them incorrectly. Stick to three or four small meals per day, rather than one large one, and be careful to feed an appropriate amount.
Make sure you provide your bubble eye with the correct aquarium setup to keep them safe and healthy.
Recommended Tank Size and Shape
Most people are surprised at how much space they really need — forget the idea of a fishbowl. Due to their relatively large size and high waste production, they need a sizable tank.
If keeping just one fish, you need an aquarium with a minimum capacity of 20 to 30 gallons, though bigger is always better. Then, add an extra 10 gallons for each additional fish you plan to keep.
If you think you might decide to add more goldfish later, choose a large enough tank to house the future number. Otherwise, you’ll just have to buy a bigger tank, and you’ll end up spending more than you need to.
Regarding shape, choose a rectangular tank that’s wider than it is tall. This maximizes the surface area of the water, ensuring it’s adequately oxygenated.
For further details, please see our article on goldfish tank sizes.
Is a Filter Needed?
They eat a lot and produce a lot of waste, therefore you always need a filter in a goldfish aquarium. Don’t listen to anyone who tells you otherwise.
The flow rate of a filter is the amount of water it cycles per hour. Ideally, you should choose a filter with a flow rate of at least 5 to 10 times the volume of your tank.
So, for a 40-gallon tank, you’ll need a filter with a flow rate of 200 to 400 gallons. With a bubble eye, you should look for a filter that won’t produce too strong a current in the aquarium, and you should also baffle the inlet to prevent their sensitive eye sac potentially being sucked in and damaged.
Do they need Substrate?
If you choose to use a substrate on the bottom of your tank, it should conform to a couple of requirements.
First, it shouldn’t be rough or sharp so that it can’t damage your fish’s eyes. Second, it needs to either be too large for your fish to swallow or so fine it can easily pass through the digestive system (for instance, sand).
While lighting isn’t a must-have for your bubble eye (as long as they’re kept in a room with enough natural light — although not in direct sunlight), many fish keepers choose to light their tanks so they can see their fish better.
Most tanks come with basic lights in the hood, anyway, so it’s generally minimal effort to light an aquarium.
Unless you plan on keeping live plants, you only need a bulb that provides about 1 to 3 watts per gallon of water in your tank.
Make sure you keep the lights on for no more than 12 to 16 hours per day and switch them off for the remaining 8 to 12. If a goldfish lives in a tank that’s light all the time, their natural sleeping and eating patterns will be disrupted.
Preferred Water Temp?
They need water between 65 and 72 degrees Fahrenheit. They don’t do well at temperatures below 60 Fahrenheit, so it may be advisable to use a heater on a low setting, just in case.
While many aquarists have kept fancy goldfish in unheated tanks without issue, ambient temperatures can dip below 60 indoors at night in the colder months, so some people don’t want to risk it.
Compatibility With Other Fish
You need to think carefully about tank mates. Although most other goldfish aren’t aggressive, they tend to swim faster, thus getting to food more quickly than the slightly sluggish bubble eye.
Video: A Look at the Bubble Eye in Action
This video shows 2 of them up close. While the tank looks to be of a right size for them, it’s worth noting that we wouldn’t recommend the sharp gravel substrate or central ornament, as they could damage their bubble eyes.
It’s debatable whether it’s right to encourage the breeding of goldfish like bubble eyes, which clearly have some health and mobility issues due to their strange anatomy.
But, if you do choose to keep them, you must ensure their environment is safe and suitable for them, bearing in mind their specific needs.
Happy fish keeping!