Water Bubble Eye Goldfish Care, Feeding, Diseases, Breeding, and More...

Introduction

The Water Bubble Eye Goldfish is one of my favorites.  I have kept and bred them for many years.

Water Bubble Eyes are often confused with Celestials because of their upturned eyes. 

The eyes are forced upwards from pressure caused by the fluid sacs that develop underneath the eyes.

They are amongst the most developed of all the Goldfish varieties and are as far removed from the Common Goldfish as you can get.

They have some special care needs and aren't suitable for beginners.

The fluid sacs are extremely fragile on fish with large sacs and are often burst.  They do re-inflate, but the size is smaller and often misshapen.  This isn't a problem for breeders, but the fish can't be used for show purposes if the sac sizes are uneven.

Last Updated: 02-15-2025 by Grant Lord.

Water Bubble Eye General Care Guidelines

Special care is required for Water Bubble Eyes.  Note these important rules:

• Don't keep them with normal-eyed varieties or other fish species unless a special feeding regime is used.
• Give them a varied diet, especially as they get older, to avoid swim bladder problems.
• Keep sharp objects out of their aquarium.
• Don't clutter their tank with plants or ornaments; there should be as little clutter as possible with lots of open space.
  
• Any gravel substrate must be smooth.

Water Bubble Eye History and Origin

All Goldfish varieties can be traced back to the Prussian or Gibel carp.  Through selective breeding of fish that developed odd genetic characteristics such as gold coloration and twin tails, all 100 plus different varieties have been created.

All Goldfish varieties have the same scientific name of Carassius auratus auratus var., not Carassius gibelio, which is interesting because no variety of Goldfish lives in the wild (unless introduced intentionally), not even the Common Goldfish.

The consensus is the Water Bubble Eye was developed in China.  The Bubble Eye was developed from the Toadhead, which lacks a dorsal fin, has upturned eyes and small bubbles.

Physical Characteristics

What Should a Water Bubble Eye Goldfish Look Like?

The Water Bubble Eye's eyes start as normal eyes. 

The fluid-filled sacs start developing at about 4 weeks, and it takes up to a year for them to fully develop.

• The scale type can be metallic, nacreous, or matt.
• The bubbles should be symmetrical.
  
• The body depth should be at least 65% of the body length.
• The dorsal is absent, and the rest of the fins are paired.  The tail fins should be divided, even in size and shape, and should have no curled or bent extremities.
  

The body shape and fins can be quite long on some strains.

Scale Types of Water Bubble Eye Goldfish

Water Bubble Eye Goldfish are represented in the three main scale types: metallic, matt, and nacreous (calico).

The most popular type is metallic.  The metallic scale type can be one or two colors, one being white.  Any black on a fish not intentionally black will be due to injury, or the fish will still be going through its color change.

Young metallic Water Bubble Eyes under 30 days old are a drab grey, but depending on several factors such as water temperature, food, sunlight, and genetics, the young fish start to darken from around eight weeks.  In strong sunlight, the juveniles will turn black, but inside, you may only see a slight darkening before it slowly fades into light gold, starting from the lower belly and moving up to the dorsal area.

When nacreous Water Bubble Eyes are bred, all three scale groups are produced.  Approximately half the fry will have nacreous scales, 25 percent will have matt scales, and the remaining 25 percent will be metallic.

The metallic specimens often take a long time to change color, if they do change color at all.

Feeding and Diet

Being deeper-bodied, Water Bubble Eyes will suffer digestive problems if they are fed low-quality food with insufficient vegetable matter and live food included in the diet.  This typically shows up as buoyancy problems with the fish bouncing on the surface with an intestine full of gas.

Gel foods are recommended as they mimic Goldfish's natural foods, which are, in the main, soft and moist.

Live foods can include mosquito larvae, daphnia, earthworms, blood worms, white worms, and adult brine shrimp.

If live food is hard to find or grow yourself, many specialist fish shops have the frozen equivalent.

I wouldn't collect daphnia from the wild as parasites such as lice can be introduced into the aquarium.

Mosquito larvae are easy to raise, and Goldfish of all ages love them.  Check whether you are legally allowed to raise them, as you can't in some countries and US states.

How much, how often, and what to feed your Goldfish depends on age, season, or whether you are conditioning your fish for breeding.

Because Goldfish only have rudimentary stomachs, they graze continuously, which is why they always appear hungry.  Ideally, they should be fed 3 times a day, but for most, this is impracticable.

Adult fish should be fed between 1-2% of their body weight daily.  If only one feeding a day is possible, a good quality food that won't dissolve before the fish can eat it is needed.  This is why I feed and recommend a gel food such as Repashy Super Gold.

The danger of overfeeding is often the reason given to feed only what can be consumed in a few minutes.

Fact: Goldfish cannot be overfed!  Goldfish are slow eaters compared to some fish species because they only have a rudimentary stomach.  They force as much food as possible into their mouths and slowly chew and swallow it before looking for another mouthful.

During this period, dry, processed foods are dissolving.  When the fish are looking for their second or third mouthful, the food has dissolved into dust that will decay and pollute the water.

More on Goldfish feeding here...

Tank Setup and Maintenance

Suitable Tank Size for Water Bubble Eyes

Water Bubble Eyes are not among the most active varieties, so one Water Bubble Eye needs 70 liters (15 imperial gallons,  18 US gallons) with a filter installed.

70 liters is a good compromise between how big the fish will grow, how big the tank is to handle, water temperature swings, and the frequency of water changes needed to keep nitrates below 30 ppm.

For each additional Goldfish, another 45 liters (10 imperial gallons, 12 US gallons) are required.

If your tank is for display purposes only, get a tank slightly taller than it is deep front to back, as taller plants such as Vallisneria can be grown, and a taller tank has a larger viewing area.

Do not place your tank where it will receive direct sunlight or strong indirect sunlight.  Even strong artificial light can be a problem.  Tanks produce ideal algae growing conditions with their high nitrate levels; all that is necessary to produce an algal bloom is sufficient light.

If you have no option but to place your tank near a strong light source, you can always install a UV clarifier.

Maintaining Water Quality

Like all Goldfish varieties, Water Bubble Eyes require good water quality to thrive.  The difficulty with this is that they can become large given the right conditions; when young, they need a lot of food to grow quickly, which produces large amounts of waste.

The ideal water parameters for Water Bubble Eye are:

• pH between 6.5-7.4
• Nitrates below 30 ppm (parts per million).  Very young fish (fry) require nitrates to be below 5 ppm.
• Ammonia needs to be at zero
• Nitrites need to be at zero
• Water temperature between 60-75^oF (16-24^oC)
• GH (general hardness) of 200 ppm or above (dGH 11)
• KH (carbonate hardness) of 143 ppm or above (dKH 8)

Most city water supplies fall into these parameters.  If your water source is from a bore, it will pay to check the water parameters, as nitrates and hardness readings can often be very high.

My water is very deficient in GH and KH, around 50 ppm and 35 ppm, respectively.

You will need a water test kit to check your water parameters regularly and determine when to make water changes.  Get a test kit that has test tubes and solutions.  Don't use test strips, as they are notoriously inaccurate.

Making partial water changes without checking whether they are sufficient or often enough is just guessing.

Filtration and Heating

A filter, although not essential, does reduce the maintenance workload.  Water changes must be made much more frequently to keep ammonia at a safe level if a filter is not installed.

Once it is cycled, a filter removes dangerous ammonia and nitrites, creating less harmful nitrates.  A water change becomes necessary once the nitrate level goes above 30 ppm, which is why you need a water test kit.

Water Bubble Eyes are not the strongest swimmers; a filter should turn the aquarium water volume over four times an hour but not create a current the fish have to swim against.

Water Bubble Eye are warm water fish, not cold water, not tropical, and prefer seasonal temperature changes.

Goldfish can take very low temperatures but only briefly, such as in winter when they enter a dormant or low activity state.  Low water temperatures like these are best tolerated by less developed varieties such as single-tailed Comets and Common Goldfish. 

A heater is not required if kept indoors, where water temperatures will be well above freezing.  If Water Bubble Eye are kept outside in a pond, and water temperatures are expected to fall below 7^oC (45^oF) for extended periods over winter, bringing them inside would be wiser.

Fancy varieties of Goldfish often develop buoyancy problems if subjected to long periods of cold water temperatures.

Plants and Substrate

Goldfish are omnivorous, meaning plant material forms part of their diet.
If you choose the wrong plants, your Bubble Eyes will strip them to stalks within hours.

Suitable plants are:

• Vallisneria - used as a background plant because of the height it grows to
• Blue Hygrophila – used as a foreground plant.  There is a dwarf variety available.
• Hygrophila Difformis – used as a foreground plant.  Its fast growth helps control algae
• Red Bacopa – the leaves get a red tinge on the underside
• Ludwigia Arcuata – this plant requires a relatively large amount of light before forming a red stem and leaves.

Adding substrate or having a bare bottom tank is a personal choice, but there are some considerations before purchasing substrate:

• White substrate will cause your fish to lose color intensity.
• Sand is not a good choice if you want to install an under-substrate filter.  The grains need to be between 3 and 6mm in size.
• Goldfish will choke on small pieces of smooth gravel.  I have lost two Black Moors from this.
• Are you planning on growing live plants?  Plants can be grown in containers if you don't want to have substrate.

Aquarium Decorations

Because of their poor eyesight, Water Bubble Eyes tend to blunder around an aquarium.  They can easily burst a bubble sac on any hard object If startled.

The bubble sac will re-grow but is often smaller or misshapen.

Decorations with holes or confined spaces should also be avoided, as if it's possible to get stuck, Goldfish invariably will.

Suitable Tank Mates for Water Bubble Eyes

The most common mistake novice Goldfish keepers make is to mix fancy varieties with single-tailed varieties.  They don't realize that slow-swimming, poor-sighted varieties such as Water Bubble Eyes can't compete successfully with fast-swimming, normal-eyed varieties for food.

What happens over time is as the single-tailed fish get the majority of the food, they get bigger and bigger, and the Water Bubble Eye slowly starves.

This even happens if you keep Celestials or Water Bubble Eyes, both highly developed varieties, with Moors.  The Moors will out-compete them for the majority of the food.

Water Bubble Eyes can be kept with other Goldfish varieties, but a suitable feeding system will need to be devised if they are.

Plecos and Bristle Nose catfish used for removing algae can become a problem if they start eating the slime off the sides of your Water Bubble Eye as a protein supplement to their diet.

Any other small fish or aquatic life in the aquarium will be eaten if it can be caught and fits into your Water Bubble Eye's mouth.

Health and Diseases

Water Bubble Eyes are no more susceptible to diseases than any other fancy Goldfish.  However, any Goldfish living in poor water conditions will develop a weakened immune system that will allow the fish to be attacked by parasites, bacteria, or fungal spores, which, unless treated, will kill it.

They are often kept with varieties they can't compete with for food, such as Comets.  The Water Bubbles Eyes won't get enough food, so they will weaken until eventually succumbing to disease or starve to death.

This is why many Goldfish enthusiasts think Water Bubble Eyes are a weaker variety that tends to get sick and die.

The lifespan of a Water Bubble Eye is no different from any other fancy variety; when well cared for, they can easily live for 10 years in an aquarium, more if living in a pond.  I have 8 year old fish still breeding successfully.

Apart from starvation, the biggest killer of adult Water Bubble Eyes is swim bladder disorder.  The condition itself isn't fatal, but it leads to other complications that ultimately lead to death.

Poor diet in older Water Bubble Eyes is the usual cause of swim bladder disorders.

Parasites

Several types of parasites attack Goldfish:

• Flukes if the body length of the fish is under 52mm (2 inches)
• Intestinal worms
• Protozoan parasites such as Costia and Ich (white spot)
• Free swimming aquatic parasitical crustaceans such as anchor worm and lice.

Bacterial Diseases

Bacterial infections can show as;

• Fin rot
• Bacterial gill disease
• Mouth rot
• Pop eye
• Raised scales
• Body sores (ulcers)
• Red patches on the body and fins

Fungal Infections

Fungal infections are quite common in Goldfish.  They are usually seen as large or small tuffs of white cotton wool-like matter on the skin or fins.

A much more serious fungal infection is Branchiomyces, an aggressive fungus that kills fish by destroying gill tissue.

Viral Pathogens

The two most common viruses are:

• Lymhocystis virus, which appears as a white crusty growth on the skin and
• Papillomatous lesions caused by the cyprinid herpes or carp pox virus.

Both look very similar, but the treatment is different.  Both are weakly transmissible, but neither is fatal.

More on Goldfish diseases here...

Eye Bubble Injuries

The large bubble sacs under the eyes of this variety are particularly susceptible to damage.  Owners sometimes find their Water Bubble Eye with a damaged bubble.  Another aquarium inhabitant or aquarium decorations can cause this.  Another common danger is filter intake tubes.

Losing a bubble doesn't bother Bubble Eyes particularly, but I would place the fish into a mild salt bath to guard against any infection and because quite a large amount of body fluid is lost.

If the fish is eating well and active, it can be returned to the aquarium after a few days. 

Other aquarium inhabitants, including larger Goldfish, can easily damage a bubble of a Water Bubble Eye, which is another reason why they should not be kept with other varieties or species of fish.

Quarantining New Fish

Quarantining new fish does not mean keeping them separated from your existing fish population for a few weeks and observing if they develop a disease.

It is unlikely fish being kept in pristine quarantine conditions and being fed high-quality food will succumb to any disease.

But what if the new fish are carrying a few parasites, such as flukes within the gills, and do not exhibit any symptoms?

And what if your fish have low immunity to flukes as they have never been exposed to them before?

It should be assumed your new Water Bubble Eye has parasites and should be treated for them.

A mild salt bath at the same time will take care of any bacterial or fungal infections that aren't obvious at the time of quarantining.

An additional benefit of salt is that it boosts the Goldfish's immune system.

Breeding Water Bubble Eye Goldfish

In theory, Water Bubble Eyes shouldn't be harder than any other variety to breed.  However, Water Bubble Eyes seem to be one of the harder varieties to get a sizeable fertile spawning.

Hand spawning is a good option for these Goldfish, but I have also bred them naturally.

The fluid sac trait is reasonably strong in the Water Bubble Eyes I have bred.  Uneven sizes were the biggest problem.  The brood also had a reasonably high number of dorsal fins, spikes, and irregular backs that required culling.

The male having a dorsal fin didn't help, but I got about 25 excellent fish for breeding.  When they were bred, the cull rate was very high because of the throwback factor to the grandparents.

Water Bubble Eye Goldfish need to be viewed from the side in an aquarium as soon as dorsal fins start to show to enable fish with them to be culled out.  Back profiles can also be viewed for smoothness and contour.

Don't be surprised if half the fry, if not more, need to be culled at this stage.

The bubble sacs under the eyes make it harder for the male to find the female.  Don't clutter the breeding container so the female can hide.  Use as many males as possible per female; the more, the better, as it increases fertilization rates.

Male/female differences are less obvious outside the breeding season because of the short, round body shape.  The female will often have a slimmer body shape than the male, giving the impression that she is a he.

The white tubercles on the male's operculum (gill plates) and leading edges of the pectoral fins in the breeding season are easily seen.  They are a good indication that the fish is in breeding condition.

More on breeding Goldfish here...

Summary and Key Facts

Country of Origin: China

Maximum size (body length): 150mm (6 inches)

Caudal Fin: Paired, can be short and stiffly held or long and forked

Dorsal Fin: Absent

Anal Fin: Paired

Scale Type: Represented in all three scale types

Eyes: Normal, with fluid-filled sacs under the eyes which tend to push the eyes upwards

Distinguishing traits: Fluid-filled sacs underneath the eyes, no dorsal fin

Breeding:  The fluid-filled sacs under the eyes make it harder for the males to find the female and the female to find the spawning medium.  When large sacs are present, swimming is also an effort.  Don't clutter the breeding container, as the fish have difficulty moving around.  Use as many males as possible per female, the more the better.  

Male/female differences are less obvious outside the breeding season because of the shorter body shape.  Often, the female will have a slimmer body shape than the male, giving the impression she is male.

The white tubercles that appear on the male’s operculum (gill plates) and leading edges of the pectoral fins in the breeding season are the best indications of gender.

Special requirements: Not to be kept with other Goldfish except Celestials.

Top of Water Bubble Eye Goldfish page