Celestial Goldfish Care, Feeding, Diseases, Breeding, and more...

Introduction

The Celestial got its name from its upwards “celestial” gazing eyes.

The Celestial's eyes start as normal eyes.  After about six to seven weeks from spawning, the eyes begin to move outwards, then upwards, taking up to six months to complete the process.

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

Therefore, they have some special care needs and aren't really suitable for beginners.

The Celestial Goldfish is often confused with the Water Bubble Eye Goldfish because they both have eyes that are upwards-looking

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

Celestial General Care Guidelines

 Special care is required for Celestials.  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 tank
• Don't clutter their tank with plants or ornaments.

Celestial 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.

Celestials first appeared as a direct mutation of the telescope Goldfish in the 18th century.  There is some debate about whether Celestials were developed in China or Korea.

They are amongst the most developed of all the Goldfish varieties.  They are far removed from the Common Goldfish that started the creation of all the fancy varieties.

Physical Characteristics

What Should a Celestial Goldfish Look Like?

The Celestial's eyes start as normal eyes.  After about six to seven weeks from spawning, the eyes begin to move outwards, then upwards, taking up to six months to complete the process.  When complete, the eyes should look straight up, with the same upturn and size in each eye.

• The eyes should look upwards.
• The body depth should be at least 65% of the body length.
• The dorsal is absent.
  
• All fins are paired.  The tail fins should be divided, even in size and shape, and should have no curled or bent extremities. 

Scale Types of Celestial Goldfish

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

The most popular type is metallic.  The metallic scale type is one or two colors.  Any black on a fish will be due to injury, or it will still be going through its color change.

Young metallic Celestials 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 Celestials 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, Celestials will suffer digestive problems if 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.

Tank Setup and Maintenance

Suitable Tank Size for Celestials

Celestials are not among the most active varieties, so one Celestial 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, the Celestial requires good water quality to thrive.  The difficulty with this is that Goldfish 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 Celestials 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) between 130-200 ppm (dGH 7-11)
• KH (carbonate hardness) between 89-142 ppm (dKH 5-8)

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 often nitrates and hardness readings can 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.

Because Celestials 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.

Celestials 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 Celestials 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 for winter 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 Celestials 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, Celestials tend to blunder around an aquarium.  They can easily knock an eye on any hard object if startled.  The eye structure can be cut if the aquarium has any sharp edges.  

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 Celestials

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 Celestials 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 Celestial 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.

Celestials 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 Celestial 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 Celestial's mouth.

Health and Diseases

Celestials 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.

Unless the other Goldfish are  Water Bubbles Eyes, the Celestials won't get enough food, so they will get weaker and weaker until eventually succumbing to disease or starving to death.

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

The lifespan of a Celestial 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.

The biggest killer of adult Celestials, apart from starvation, 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 Celestials 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

Eye Injuries

The large protruding eyes of this variety are particularly susceptible to damage.  Owners sometimes find their Celestial with a damaged or missing eye.  Another aquarium inhabitant or aquarium decorations can cause this.

Losing an eye doesn't seem to bother Goldfish particularly, but I would place the fish into a mild salt bath to guard against any infection and because quite a large amount of blood is lost.

If the fish is eating well and active, it can be returned to the aquarium after a few days.  With a missing eye, it is now at a disadvantage compared to fish with two eyes, so during feeding, it will need to be monitored to ensure it is getting its fair share of food.

Other aquarium inhabitants, including larger Goldfish, can easily suck an eye out of a Celestial, which is another reason why Celestials should not be kept with other varieties or species of fish.  A Celestial shouldn't be significantly smaller than other Goldfish in the same aquarium.

More about Goldfish diseases here...

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 Celestial 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 Celestial Goldfish

In theory, Celestials shouldn't be any more difficult than any other variety to breed.  However, Celestials seem to be one of the harder varieties to breed. It is hard to get a sizeable fertile spawning.

The upturned 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.

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

The eye trait seemed reasonably strong in the specimens I have bred, but there are always some where the eye development stops partway through the process, or one eye doesn’t develop as fully as the other.

Each brood also a reasonably high number of dorsal fins or spikes.  As with all varieties that aren't meant to have a dorsal, they need to be viewed from the side in an aquarium as soon as dorsal fins start to show.

Cull out any that show such faults.  Back profiles can also be viewed for smoothness and contour at the same time.

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

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

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 that appear 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 about breeding Goldfish here...

Summary and Key Facts

Country of Origin: China/Korea (there is some debate regarding origin)

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

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, but metallic is the most common

Eyes: Upturned with some fish able to look into their own eyes

Distinguishing traits: Upturned eyes, no dorsal fin

Breeding:  The upturned eyes make it harder for the males 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.

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 varieties except Water Bubble Eyes.

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