One of the easily recognizable fishes in your aquarium is the telescope goldfish.

With the multi-color appearance and long floating fins, these telescope eye goldfishes are attention-seeking because their large outbound eyes look like a small movable volcano in the water.

They belong to the species of goldfishes, which are traditionally among the favorites of aquarium lovers. They are funny and attractive, and some also come with long feathery fins & tails resembling a butterfly, commonly known as butterfly telescope goldfish.

The big eyes of the fancy goldfish are the main fascinating features as they are round and protruding, which is why these are also known as Dragon Eye fish; quite evident as their origination region is China.

Read through the article below about all the necessary information on their origination, lifecycle, breeding, aquarium tanks, and much more.

A Brief Review of the Species

Quick Species Facts
Scientific Name Carassius Auratus
Other Common Names Dragon Eye Goldfish, Dragonfish, Globe Eye,Demekin
Family Cyprinidae (Minnows & Carps)
Origin Southeast Asia (Primarily China)
Lifespan 10-20 years
Size 5-8 inches
Type Freshwater Fish

History of Telescope Goldfish and its Suitable Habitation

For hundreds of years, goldfishes have been a cute preference for fish lovers as the colorful scales with floating long tail is like an ornament attached to the body.

The telescope eye fish has historical evidence found almost three centuries ago when in the 1700s, a peculiar formation was developed in the goldfish around the regions of current China.

Later these fishes reached Japan via trade route and were locally named Demekin, translated as telescope goldfish.

These new formations in the goldfish were the poking eye that seemed circularly connected on the head and looked attacking to the enemy.

The proverb old is gold goes hand in hand with the goldfish since the bulging eyes genuinely enhance its beauty while bright coloration on the scales and fanning tail in the back facades a sharp attitude in the aquarium.

These telescope goldfishes are naturally found in still water bodies or streams with low flow rates. It can comfortably inhabit freshwater of ponds, rivers, lakes while relying on small plants, detritus, and insect larva.

 Approximate Length of the Species: How Big do Telescope Goldfish Get?

The goldfishes are usually small in size of about 4 inches but are also observed to reach up to 10 inches in favorable conditions regarding the temperature and food particles.

The telescope goldfish gathers an approximate length of 5 inches and, in some cases, may even increase up to 7 or 8 inches. Here, the eyes extending out are approximately 1.5 to 2cm long.

But the telescope eye goldfish also has typical variations depending upon the color and size of the stalk eye protruding out from the body.

The black moor or black telescope goldfish is a popular variant of this species, which is black and is between 4 – 10 inches. The panda telescope goldfish is another variant that reaches 7-8 inches in length.

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Characteristics & Display Patterns

These telescope eye fishes appear in intensely bright colors despite the name goldfish. The butterfly telescope goldfish looks fascinating with multiple patterns & shades.

There are numerous telescope eye goldfish discovered to date that are diversified into categories depending upon their shades, characteristics, and eyes.

The usual telescope goldfish is round in shapes like an egg with a larger head area and velvety scales of about 30 in lateral numbers. The translucent butterfly fins give it a style while the stalking eyes bulge out at the average age of 6 months.

The black moors initially have metallic scales that turn to the dark black surface, and in some specific conditions, they change their color to gold or orange & referred to as orange moor goldfish.

The panda telescope goldfish, like its name, has mixed patterns of black and white strips over the scales and eyes poking outwards from the sides.

There are other variations named after their color, such as white, red, and yellow telescopes, which pose different structures of eyestalks. Other popular types are calico butterfly telescopes, fantails, Celestial eye goldfish, etc.

Telescope Goldfish-Selfcare Guide

What is the Average Lifespan of Telescope Goldfish

It is usually observed that the goldfish can live up to 20-25 years in total age, but the bug-eye goldfish, due to its specific characteristics, stays up for about 10-15 years.

If the fishkeeper is well informed and manages to fulfill the basic requirements to maintain optimum habitation conditions, then the telescope eye goldfish may live for 20 years.

But the facts and figures collected from the owners suggest that it is hard to maintain a telescopic eye for long years as they are slow swimmers and vulnerable.

The protruding eyes cause poor vision, which at times create trouble to feed themselves even though the ample particles lay untouched on the aquarium floor.

Author Note: We recommend keeping the telescope goldfish either in separate water or with other slow-moving non-predators, which will keep them safe to flow a long life of up to 12-15 years or more.

Telescope Goldfish: Male/Female

Goldfishes, in general, pave a difficulty for the breeder to identify its gender, and it is tricky and almost impossible to check if your telescope goldfish is male or female.

So, gendering these fishes is only possible during the breeding season when the female partners tend to gain weight as they carry eggs, while males look slightly smaller.

But this situation only occurs twice a year, only after the fish ages one year and above when they are mature enough to mate.

You can test the telescope goldfish through the gill covers and pectoral fins, which can be observed near the bottom from the front of the stomach.

While checking out the fins and covers, if a small bruise or contusion, known as tubercles, is observed, the fish is a male. They generally appear during spawning season and may even appear over gills or faces.

Another recognizable feature of the male fish is the unusually long vent and concave in shape, while there is a ridge-like structure under the stomach. These structures are absent in females.

Pro tip: Do not worry if your newly purchased telescope goldfish sits calmly on the surface, as these fishes take more time to adjust to the local conditions than other tank mates. It usually swims on the character in the initial days to get familiar with the area and other fishes.

Cost of Petting a Telescope Goldfish

Goldfishes are generally not too expensive and are purchasable globally from west to east. Provided they comfortable adjust in the dwelling regarding temperatures and other constraints.

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However, the telescope goldfish is luxurious due to its ornamental design and appearance. These fishes with basic coloring are not too expensive, while those with attractive features are charged well.

Altogether the price of these fishes varies from continent to continent. Still, the average price of the bug-eye goldfish ranges from $30 to $40, and sometimes even higher depending upon the size, color, age, eye bulge, etc.

Expert tip: We recommend keeping the telescope goldfishes with small-sized harmless fishes. They pose vulnerable eyes to the envious bigger mates who tend to grab and eat it if they get a chance, and the goldfishes cannot defend it.

Specific Care Guidance

Quick Care Facts
Care & Maintenance Moderate to high
Social Adjustment Must only be kept with similar variants or harmless mates
Nature Calm and harmless
Diet Both plants and worms (fresh &flake)
Breeding Process Gentle

What & How to Feed the Telescope Goldfish?

Goldfishes are among the simplest omnivore aquatics and easily survive over fresh or frozen foods and even flakes. So, you may feed them with –

  • Boiled vegetables
  • Pellets
  • Meatballs
  • Live worms
  • Insect larva
  • Shrimps

It is advised by the expert telescope goldfish breeders to put them over a frozen diet that is genuinely healthy and free of bacterial infections.

Expert tip: The butterfly telescope goldfishes have weak eyesight, and hence sometimes, it becomes difficult for the fish keepers to feed them. They cannot find the food particles and instead consume the surface algae, creating an infection in the stomach.

 So, if you wish to pet these telescope goldfishes in your home aquarium, you must have the patience to keep checking if they are feeding well while providing food many times a day.

General Nature & Behavioral Patterns

These are among the polite and peace-loving creatures in the aquariums or ponds and prefer to move slowly & steadily in the water. They do not predate their mates in the surroundings.

Although sometimes the wild telescope eye fishes are observed attacking the predators of the lakes, which is generally due to facing environmental extremisms, otherwise they are friendly natured.

They usually suffer due to other species in the water bodies that may find them easy prey, which cannot retaliate if attacked.

Hence it is necessary to put them with similar variants or fishes of the same size and nature, such as Diamond Tetra, Rubber Lip Pleco, etc.

How do the Telescope Goldfish Breed

While in natural water bodies, the telescope eye goldfish require specific environmental conditions, mainly corresponding to the warm season around April and August, along with mature & healthy mating partners.

Breeding the goldfish in an aquarium becomes tedious since these parent fishes lay eggs on the plants and eat them. So it becomes a rigorous process to protect the eggs and get them hatched.

Hence, the breeding process requires continuous water monitoring to maintain optimum temperature freshness and protection of eggs after spawning.

Equipment Required for Breeding in the Tank.

The usual equipment needed in telescope goldfish breeding is a tank with a sufficient size capacity of about 15 to 20 Gallons or even bigger if there are multiple pairs of goldfish.

Water filters and heaters to maintain freshness and warmth.

Aquatic plants or artificial spawning mops are necessary for the fish to lay its egg as it has hair-like features that get stuck to the plants or mops.

Pro tip: You can create the spawning mops at home using green color wool, which is fibrous in texture and can perfectly attach with eggs.

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The oxygenating system is also needed sometimes, and it is also advised to provide protein-rich food such as blood worms or flakes, which helps reproduction.

Initiating Mating Process of Telescope Goldfish

To begin the reproduction process, you need to create a moderate temperature in the water tank, around 12 to 15 degrees Celsius. Place the plant or mop into the water to create a natural environment favorable for goldfish breeding.

You can pour the fish (both male & female) into the tank and give it some time to adjust. The temperature can be slightly increased up to 19 to 22 degrees Celsius, suitable for mating.

You should leave the fishes undisturbed, and as the temperature rises, the male goldfish gets provoked for reproduction and start following the females. This is when the color change is observed in the fish.

The male goldfish start pushing the females towards the bushes or mops. The spawning process leads the females to lay eggs on the mop, which their male partners start fertilizing.

Egg Hatching and Fry Protection

After the fertilization process, you can remove the spawning mop from the tank to protect the eggs, as the parents will start eating them before hatching.

The fertilized eggs may take up to 3 or 4 days, sometimes even more as per the temperature conditions, and tiny baby fry comes out of it, usually dark brown or black. Usually, the dark shade eggs do not hatch as they are not appropriately fertilized.

Pro Tip: You must monitor the fry tank to feed special fry foods and maintain moderate temperatures with water filters at regular intervals. The nutrition of large fish can also be given provided it is crushed into small pieces. Keep the fry away from large fishes until they become at least 3cm long, which takes a few months.

Ways to Keep Your Bug Eye Goldfish Healthy

The telescope goldfishes pose princely characteristics amongst their mates as they are sweet and delicate. Slight neglect or mishandling of the living environment may trouble the health conditions of these fishes.

Cause of Illness

One of the common reasons these fishes get illness is the polluted water conditions, which may occur due to the long duration of water filtering, as it lives healthily in clean water.

Another apparent reason that causes lousy health in these fishes is the food material. Being omnivore creatures, they are fed with meat or living worms, shrimps, etc., for proteins, which at times is unhealthy.

Types of Diseases Affecting the Goldfish

  • Bacterial Infection
    Primarily the telescope eye goldfish catches bacterial infection from stale food particles left uneaten on the floor and created fungus. The protozoan or parasitic diseases are caused by the infected larva, warms, etc. Feeding with goldfish unique flakes or frozen food is recommended instead of living creatures.
  • Swim Bladder
    Suppose you observe your telescope goldfish not swimming correctly. In that case, it may be suffering from swim bladder illness caused due to unsuitable food items, leading to constipation or parasitic infection. It may also be due to some injury, and you must closely examine the fish.
  • Ich, Costia, and Chilodonella
    Another troubling situation observed in these fishes is when white spots appear over the scales. It is a protozoan disease known as Ich, which can be fatal if left untreated. Similar to Ich are Costia and Chilodonella, which causes cloudiness.
    The black spot Ich is a parasitic disease common in fishes but not fatal.
  • Flukes
    Flukes or flatworms may also trouble your fish which attach themselves to the mouth of the fish but is treatable. Similar to Flukes are Argulus and Anchor worms that stick to the goldfish’s body.
  • Dropsy & Tuberculosis
    Dropsy affects the kidney while tuberculosis attacks the belly portion, and both are untreatable in most cases leading to death.

Author Note: Cloud eye is another unusual condition in these telescope eye fishes, caused due to unknown reasons.

Tank Suggestions

Quick Tank Facts
Minimal Water Capacity 10 Gallons (or more) per fish
Water Temperatures 18 to 23 degrees Celsius
Water Hardness 5 to 19 dGH
Water Ph Level 6 to 8
Brackish Occasionally (Salinity – under 10%, gravity below 1.002)

Average Tank Size

Expert breeders of telescope goldfish suggest a standard tank size is 10 Gallons, although some still promote 20 Gallons of the water tank as the minimum capacity to live comfortably.

Goldfishes attain an average length of 6 inches, and with favorable conditions, they may even increase longer. So, to avoid creating a fussy situation for both the fish and the owner, it is recommended to begin with a 20 Gallon tank and keep on increasing the tank size with further addition of fishes in the future.

Setting up an Aquarium for Telescope Goldfish

Since these telescope eye fishes have poor vision and cannot swim fast, an aquarium with horizontal stretch is advised to install. Fishes may not feed properly in deep water tanks as they wouldn’t easily reach the surface.

Few pieces of equipment are described below, which must be placed inside the tank so that the fish feels naturally at home.


Small plants look beautiful in aquariums and help during the matting process as well, and here is where the fish feels at home. However, since telescope goldfish, like other goldfish, consume vegetation, they will eat almost any aquatic plant.

Don’t be discouraged, though. There are still a few plants that no fish eat, such as anubias and java fern. Therefore, you are free to include them in your tank.

Artificial plants made of silk can also be an alternative for live plants.

Quick Tip: Avoid the Java Moss in their tank if you don’t want your telescope to get trapped in it.


Telescope goldfishes love to forage over underlying substrates or small pebbles in the aquarium. Aquarium sand or fine gravel is most suitable for keeping inside the aquarium and enables some enjoyable activities inside.


It is essential to put up delicate dim lights inside the goldfish tanks to avoid staying in the dark for too long. Small colorful lights with a faint tone are best suitable for these fishes.

Filtration & Oxygenation

Goldfishes tend to create a lot of waste in their space; hence it is necessary to keep cleaning the water regularly. Unclean water is harmful to its health; thus, an oxygenation system works best with the water filters as it helps maintain freshness. You can also opt for a self-cleaning fish tank.

Water Parameters

Goldfishes are one such species that naturally survive both cold and warm waters. However, it is essential to maintain a moderate temperature inside the tank to keep your pet healthy.

In general, a temperature range from 16 degrees Celsius to 24 degrees Celsius is ideal for these fishes. You must also check the water hardness and Ph levels, and temperature.

Telescope goldfish can easily withstand the hardness level of 5 to 19 dGH, while the Ph levels should be maintained between 6 to 8.

Few Tank Mates

The telescope goldfish are too fussy when sharing space with another species. These can comfortably thrive with species that are similar in size and characteristics.

Hence, they should not be kept with Tetras like Silvertip tetras, Oscars, Platys, Swordtails, Plecos, etc.

The apple snails are one of the most suitable telescope goldfish tank mates that defend from getting eaten up and at the same time give an excellent design to the fish aquarium.

The other peaceful variants of goldfish are also suitable to be kept in the same space with these fishes, such as –

  • Black telescope goldfish
  • Orange moor
  • Panda telescope goldfish

Frequently Asked Questions

Q. Can the telescope goldfishes grow back its eyes?

A. Eyes of the telescope goldfish are pretty vulnerable to attacks from their mates as they prey on them for food. So, it is pretty apparent that they face injuries, but it is seen that these fishes quickly recover their eyes and vision in a few months.

The nerve cells are regenerated in 1 or 2 weeks of injury, while complete recovery may take 2-3 months.

Q. How do I know if my calico telescope goldfish requires more oxygen?

A. Goldfish gives a clear signal of low-level oxygen in the tank when it is observed to be yawning over the surface. Goldfishes do not yawn, but it is a clear symptom of the need for oxygen, and you can work it instantly.

Q. Why do the fancy goldfish’s big eyes turn black?

A. Though the color change in the fish’s eyes signals health conditions, black coloration in the goldfish eyes is a regular phenomenon and has nothing to worry about.

Q. Does the telescope eye require saltwater in the tank?

A. Yes, there are some aquarium salts available which are the best source of electrolytes in the fishes. It helps recover from infections and improves oxygen and carbon dioxide levels.

Q. How does the bug-eye goldfish sleep?

A. These fishes have a unique pattern of sleeping. They do not lie down on the surface or hide in the shrubs while asleep. Instead, they are observed to float effortlessly in the water while being stable.

The body color starts fading until the resume from the sleeping posture.

Q. Is it necessary to avail lights in the goldfish tanks?

A. It is evident that the living organisms rely on the regular day/ night cycle, and hence providing lights and creating darkness in specific time helps maintain metabolism and good health of the fish.

Q. Why does the goldfish sits at the bottom of the tank?

A. There can be multiple reasons for the goldfish to sit at the surface. It is usually seen with this gesture during stressful situations, especially when there is a lot of disturbance in the water.

Whether water is unfiltered or due to lack of oxygen, the fish is observed to sit at the bottom.

Final Takeaway: Should you get these fancy fish in your tank?

For hundreds of years since the redevelopment of goldfishes, the new species have equally taken space for petting and breeding. These harmless and peace-loving creatures pose a lovely appearance in the home aquariums.

The knowledgeable fishkeepers can easily handle the breeding process and put the telescope goldfish for sale by fulfilling commercial purposes.

Since they are not very large and quickly adjust in the artificially created homely environment, one can start with 2 to 3 pairs of telescope goldfishes in their tanks.

About the Author

Shelby Crosby

Shelby is a passionate fishkeeper who has been writing about fish for over 5 years. She is a pro aquarist and holds a BSc Honors Degree in Wildlife and Fisheries. She creates her own beautiful aquarium layouts and loves to share her knowledge of tropical fish with other hobbyists.

Career Highlights:

  • Has worked with several aquarium manufacturers as a consultant
  • Organized and hosted workshops on freshwater fish keeping at retail stores, educational facilities, and libraries
  • Released content for the amphibian community through her writings

Educational Highlights:

  • BSc Honors in Wildlife and Fisheries in 2011 (University of Northern British Columbia)
  • Completed her undergraduate thesis on the effects of zoochlorella supplementation on the growth and health of fish.

Writing Experience

Miss Crosby is a Freelance blogger; many of her articles are posted online on various blogs. She has also written a few short articles for "Tropical Fish Hobbyist Magazine" in the past. She is a regular contributor to Her education, first-hand experience with fishkeeping, and in-depth knowledge in aquaculture make her one of the most competent writers in the industry.

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