telescope eye goldfish

The Telescope Eyed Fancy Goldfish

“A Big-Eyed Beauty”

The Telescope Eye goldfish is set apart from all other goldfish varieties because of the distinctive eyes that protrude on each side of its head. There’s no mistaking this beauty when in a crowd of other goldfish.

telescope goldfish

There is nothing mundane about this fish as we will find out as we explore facts and information on the Telescope Eye goldfish!

Where did the Telescope Eye goldfish come from?

Scientific Name:

Carassius auratus auratus


Carp, Minnow


Twin Tail




Peaceful, Friendly

Swimming Speed:



Other slow swimmers (Celestial, Bubble Eye)


10-15 years



Before we dig into the origins and history of the Telescope, we must first look at goldfish as a whole. Telescope Eye is a variety of fancy goldfish.

Also known as:

  • Demekin (“pop-eye goldfish”)
  • Dragon Eye
  • Dragonfish
  • Globe Eye (termed by the Goldfish Society of Great Britain)

Ancestoral History of the Telescope Eye

Goldfish originated in Japan as an invasive species living in ditches, lakes, ponds, rivers, and wetlands.  As wild fish, goldfish were known as “chi” and became a source of food for Japan and China.

Through reproducing, the “chi” (wild goldfish) began to develop vibrant colors of reds, oranges, and yellows. This coloring caused them to be the most coveted “pickings” for a meal by predators.

Buddhist monks took the “chi” and began to raise them in monasterial ponds to keep them safe from predators. However, the “chi” were still used as a food source within the monasteries.

The Buddhist tradition of performing a good deed included setting the most vibrant colored “chi” free into remote ponds. Before too long, most ponds became full of these “chi.” 

Fish hobbyists took an interest in the “chi” and began to raise and breed them around the mid-1200s. Most of the “chi” became domesticated and were raised as pets.

The “chi” came to be known as “goldfish.”

By the 1500s, keeping goldfish in earthen vessels (bowls) became the trend.

This was about the time that the selective breeding frenzy (for fish hobbyists) with goldfish began. 

The Telescope Eye Comes Into Existence

Through selective breeding of Tosakins and Ryukins (in China in the 1700s), the “Demekin” (Telescope Eye goldfish) was produced.

tosakin goldfish

The Telescope Eye did not arrive in the United States until the 1850s.

Where are the “Chi” Today?

Today, wild “chi” still exist in the waters in Asia. They are prevalent in other parts of the world living as a wild invasive species.

Somehow they escaped the selective breeding process or were tossed out as unwanted pets into the wild.

“Chi” (wild goldfish) currently thrive in the brackish waters of ditches and lagoons as well as freshwater areas. They feed on wild algae, weeds, plants, zooplankton, and garbage (literally.)

You will find the wild goldfish in muted colors of olive, brown, gray, silver, and white. They range in sizes of 2-12” long.

Amazingly, the “chi” can live up to 41 years in the wild providing conditions are just right. 


The Telescope Eyed Fancy Goldfish is one of the more docile goldfish breeds. They are naturally very sweet-natured and calm.

They can be very interactive with their tankmates as well as their owners. Most goldfish can recognize their owners and even anticipate their arrival.

The Telescope Eyed Fancy Goldfish may not be able to see their owners very well, but they can distinguish them from strangers based on their voices.

gold black telescope goldfish

Overall, these goldfish are not known for their aggression.

They should only be residing alongside similarly handicapped goldfish breeds.

Appropriate tank mates for the Telescope Eyed Fancy Goldfish include the Bubble Eyed Fancy Goldfish, the Black Moor Goldfish, the Lionhead Goldfish, and the Celestial Eyed Fancy Goldfish.

Traits and Characteristics Of The Telescope Goldfish

There is no mistaking a Telescope Eye goldfish! The features of this fish are what makes it unique and highly prized by many goldfish lovers.

The Telescope Eyed Fancy Goldfish should have a split caudal fin (tail fin) that is only partially forked.

Originally, their tail fins were often not as long and flowing as other goldfish breeds, but, they are rather moderate in length.

However, many Telescope Eyed Fancy Goldfish develop various another tail fin (caudal fin) shape including the butterfly tail shape, the broadtail shape, the veil tail shape, as well as long and flowing tail fins.


The Telescope Eyed Fancy Goldfish’s most prominent feature is their unique eye shape.

The eye formations may not fully begin to take shape until the goldfish is five or six months old.

Their eyes appear to bulge out from the top of their heads in a telescoping effect. This effect is caused by the cones or stalks that are placed on the side of the fish’s head.

Sometimes the Telescope Eyed Fancy Goldfish’s eye stalks will stick out about ¾ of an inch from the base.

This fish has poor eyesight, and because of this, it is a slow swimmer.

There are three different eye shapes in this fish. Slight variations in overall appearance differ.

  • Flat (The top of the eye is flat)
  • Dome (The shape of the eye is wider at the base and more narrow at the top)
  • Round (The attachment of the eye can differ in degrees because of the rounded shape.)

The Telescope Eye goldfish has a deep, egg-shaped body with long flowing fins. Considered a twin-tail, this fish shares it’s body shape with other goldfish varieties. The caudle peduncle is thick and short. There are no scales on the head.

Other Egg-Shaped Goldfish Varieties

Single Tail Goldfish


Twin Tail ​Goldfish








Pom Pom



Celestial Eye

Bubble Eye


Vibrant colors are seen in the Telescope Eye variety. The colors evident in the fish today as compared to the colors of their ancestral fish (“chi”) is significant in contrast! Their scales can develop in multiple color varieties as well as varying patterns.

Regardless of the color or pattern of their scales, they are almost always metallic and shiny.

Colors Found in this fish today







Colors of their ancestral fish







This little fish is a slow swimmer because of its body shape and because it has poor eyesight. It is peaceful and friendly.

What level of care does the Telescope Eye goldfish require?

This fish is not good for beginners.

Telescope Eye goldfish are slow swimmers. They should never be placed with fast swimming fish or any single-tail goldfish.

Their chubby body type and poor vision make them less capable swimmers.

panda telescope goldfish

Having poor eyesight and difficulty swimming, this fish requires extra care. Although it’s listed as a hardy fish, it is delicate.

They can damage easily as a result of their unique eye development. Their eyes may be protruding and large, but their eyesight is rather poor which contributes to their potential for injury. 

Caution should be used with placing air stones and filtration systems in the Telescope Eye’s tank.

Being a slow swimmer, this fish does not do well is water that has significant movement that may be produced by these things.

The water intake of your filtration system should have a sponge or protective covering to avoid the fish from being sucked up against it.

The Telescope Eyed Fancy Goldfish can be regarded as high maintenance because of their requirements surrounding it's handicaps.

What kind of habitat do TeleSCOPE GOLDFISH like?

Tank Size:

20-30 gallons

(1” of fish per 1 gallon of water)


Other Slow Swimmers such as Celestial Eye, Ranchu, Ryukin

Does best with 5+ fish in the tank

Water Filtration System:

Required because these fish are high producers of waste

200 gallons/hour

Air Stone:

Required to keep the water oxygenated

Water Parameters:

Temp: 65-72 degrees (F)

Ammonia: <0.1

Nitrate: 3.0


Use caution because anything with sharp points can damage/injure the fish’s eyes

You should never overpopulate your Telescope Eyed Fancy Goldfish environment.

The rule of thumb to follow for a safely populated goldfish aquarium or outdoor pond is to plan at least 20 gallons of water per fish.

For example, if you want ten goldfish in the habitat then you should prepare to purchase a 200-gallon aquarium.

This may seem excessive. However, the fish do not stay small for very long, and they require room to grow, swim and plenty of oxygenated water for them to breathe.

Goldfish hobbyists say that you should purchase the biggest tank that you can afford and choose your fish quantity based on that.

Telescope Eyed Fancy Goldfish require 30% of the tank water to be replaced every two weeks.

The new water should be treated with water conditioner before being added to the tank. Filter parts or décor that need to be cleaned should be rinsed in the tank water that had been removed.

Rinsing or cleaning them in untreated tap water may cause your fish to go into shock when the object is returned.

Also, you may rinse away the beneficial bacteria.

Gravel and fish should never need to be removed from the aquarium during a cleaning.

Gravel can be cleaned by using a gravel vacuum.

Telescope Goldfish Fish Tank Décor Warning

Do not place any sharp or pointy objects inside the Telescope Eyed Fancy Goldfish aquarium.

Choose smooth décor and other still objects to decorate the tank that will not cause harm to your fish.

Your goldfish will continue to grow until they die as long as they are provided enough tank space to do so.

They should be kept in a rectangular shaped habitat. Rectangular aquariums or outdoor ponds offer your fish adequate surface area for swimming, growing as well as quality oxygenated water for breathing.

The Telescope Eyed Fancy Goldfish is a delicate fish and therefore it might be easily damaged by the filtration device, décor, or other objects inside the tank.

Telescope Goldfish Filtration

They require a filtration system that offers mechanical, biological and chemical filtration.

These three systems will ensure that floating debris and other things inside the water are removed.

However, you will need to choose a filtration system that does not have sharp edges or an intense suction or produce a strong current.

As previously mentioned; goldfish require a habitat that is not overpopulated with other inhabitants. Each goldfish should have about 20-gallons of water.

Therefore, if you have ten Telescope Eyed Fancy Goldfish, then they should be living in a 200-gallon tank.

This rule of thumb is set to provide adequate living conditions for the inhabitants without them swimming into each other.

They may do this anyway as their eyesight is rather poor. Another problem that could occur if a tank is overpopulated is excessive pollution.

More residents living inside the aquarium can result in more waste.

The more waste that is in the water (that they use to breathe) the less oxygen is available.

What do I feed the Telescope Eye goldfish?

Dry Food

You may think feeding Telescope Eyed Fancy Goldfish is a piece of cake.

You may believe that goldfish only eat Goldfish Flakes or Goldfish Pellets.

However, this is not the whole truth!

Yes, goldfish can be fed these products, and they are readily available at any local pet store. However, they actually enjoy a variety of different types of food.

Telescope Eyed Fancy Goldfish are omnivores so they will happily consume plant sources as well as meat sources.

Now, don’t think that you can offer your goldfish a Turkey leg from Thanksgiving and that they would be happy to eat it.

The truth is, their meat sources are a little different. 

Flakes or pellets purchased from a pet supply store are generally what most fish owners buy; however, there are not enough nutrients in dry food alone. Additional types of food should also be given.

Also, note that flake food remains at the surface of the water and fish are bottom feeders.

With this in mind, pellets may be a better option for your fish.

Goldfish, like the Telescope Eyed Fancy Goldfish, enjoy:

Live Food

Live food is an excellent source of protein and is perhaps the most important thing you can give your fish.

  • Brine Shrimp
  • Earthworms
  • Bloodworms
  • Daphnia

Never feed your fish anything from lakes, dirt, ponds, etc. Only feed live food that is purchased from the pet supply store. This ensures that there are no diseases that can be passed on to your fish.

Seafood Options

Telescope Eye goldfish love little bits of seafood. Make sure that if it’s frozen, thaw it completely before feeding to your fish.

Also be sure to feed them from a source you trust and not straight out of the ocean, rivers or lakes.

  • Lobster Meat
  • Mussels
  • Crab Meat

Vegetables, Fruits, and Plants

Vegetables and fruits provide a healthy source of nutrients that are beneficial to your goldfish. Before feeding to your fish, make sure it is soft and finely diced into tiny bits.

Live plants are a treat they enjoy nibbling on. Consult your local pet supply on what types of live plants you can place in your aquarium.

Also, use caution when putting too many plants in the aquarium because plants deplete the oxygen in the water when the lights are off.

  • Peas cooked (remove the outer layer)
  • Lettuce (uncooked)
  • Seaweed
  • Broccoli
  • Cucumber
  • Oranges
  • Apples
  • Live Plants such as duckweed, anacharis, azolla, salvinia
  • Algae pills

Telescope Eye goldfish should not be given:

  • Anything containing animal fat
  • Bread
  • Cooked Lettuce
  • Uncooked Peas


  • Feedings should be once or twice a day and should be done at the same time each day.
  • Feed a small pinch of food between your thumb and finger.

Regardless of what you are feeding your Telescope Eyed Fancy Goldfish, or when you are feeding them, you should never overfeed them.

Goldfish are instinctual munchers. This suggests that they will eat just about anything at any time, and they can quickly become overweight if you allow this.

Therefore, you should only provide your Telescope Eyed Fancy Goldfish with the amount of food that they can finish eating within two to three minutes time.

Uneaten food will only sink to the bottom of the aquarium, become moldy and pollute the water.

Health Concerns

The Telescope Eye goldfish has eyes that are naturally protruding/bulging. Unless you are familiar with this variety of fish, this eye protrusion could easily be mistaken for “pop-eye.”

Because of their eyes, extra care should be given to prevent injury to the eye itself. Caution should be used when placing any plants or decoration into the tank.


Pos​​​​sible ​​​​Cause(s)

Breathing Issues (gasping, rapid, staying at surface)

Poor Water Quality

Refuses to Eat

Poor Water Quality

Internal Parasites

Swimming erratically or upside down

Poor Water Quality

Swim Bladder Disease


Improper Feeding

Laying at bottom

Poor Water Quality


Reacts slowly to noise or stimuli

Poor Water Quality

Rubbing against wall of tank or other surfaces


Fungus Infection

Fins are closed, lethargic

Poor Water Quality


Fins are frayed


Fin / Tail Rot

Raised fuzzy bumps

Infection (fungal or bacterial)

Spots that look like grains of salt

Ich (highly contagious to other fish)

Black Spots

Ammonia burn


Appears Bloated, scales are raised


Fed too much

Gills are pale



Parasites (usually visible)

Eyes are Protruded

(This is a natural trait of the Telescope Eye, however, if you noticed the eye(s) becoming unusually larger it may be an indication of “pop-eye.”)



Appearance is slimy

Velvet (parasite)

Small sores on head


Ulcers (open sores on body)

Bacterial Infection

Smooth white or pink warts

Fish Pox


It is fairly easy to distinguish male from female Telescope Eye goldfish. Sexing goldfish is the same for all varieties.




  • thinner

  • longer

  • streamlined body


  • thicker

  • Rounder

  • deeper bod

Breeding Behavior: chases females, attempts to push female against tank wall

Breeding Behavior: develops roe (eggs) that cause bulge on side

Vent (anal opening):

  • concave

  • narrow

  • elongated

Vent (anal opening):

  • rounder

  • protrudes from body

Maturity Age: 9 months to 1 year

Maturity Age: 3 years

Tubercles (white spots) are present on gill shields, pectoral fins, face, scales

Female Telescope Eye goldfish spawn 3-10 times (laying eggs) at 8-10 day intervals. They will lay up to 1,000 eggs each time. The eggs are laid on any vegetation that is present in the tank. The fry (baby fish) hatches 5-6 days after the eggs are laid.

The Telescope Eye goldfish fry are not born with the characteristic protruding eyes. It takes up to 3 months for the eyes to become pronounced.

Fun Facts About the Telescope Eye Goldfish

Sleeping with Eyes Open!

Telescope Eye goldfish sleep with their eyes open.

Blah Fish Colors!

The wild variety of the Telescope Eye goldfish is muted in color compared to the domesticated variety. The muted colors are olive, brown, gray, silver, and white.

What goes in, comes out fast!

These fish don’t have stomachs. When they eat, it immediately enters the intestine and what goes in quickly, comes out quickly!

Hibernating Fish!

In the wild, these fish go into hibernation when winter approaches.

A Ring For Every Year of Life!

You can tell the age of a Telescope Eye goldfish. Every year of the fish’s life is evident by the number of rings on the scales (1 ring for every 1 year.) These rings are called circuli.

Dark Produces White!

If you keep a Telescope Eye goldfish in the dark, it will turn completely white! The fish requires light in order for it to retain its coloring.

A 41-Year Old Fish!

The “chi” is the ancestral species of the Telescope Eye goldfish. In the wild, a “chi” can live up to 41 years!


The Telescope Eye goldfish has a unique appearance with its big eyes. Its eyes give it a “pouty” look. This peaceful fish is gentle and requires special care because of how delicate the eyes are. With it being a slow swimmer, certain accommodations must be made with regard to tankmates and tank environment.

The Telescope Eye goldfish is not good for beginners and should be left to the more experienced fish enthusiast.

Telescope Goldfish Questions & Answers

goldfisho mascot

What is a Telescope goldfish?
  • Type: Fancy
  • Colors: red, blue, chocolate, white, tricolor, calico, red/white, black/white
  • Type of Swimmer: slow
  • Temperament: peaceful
  • Single or Twin-tail: twin
  • Level of Care: not for beginners
What does a Telescope goldfish cost?
  • $5 - $10 each
What are compatible tank mates for Telescope goldfish?
  • Because Telescope are slow swimmers, never place them together with fast swimming fish. They are best with other slow swimming fish such as Lionheads, Bubble Eyes, Black Moors, Fantails, or Butterfly Tails.

Note: Slow swimming goldfish should not be placed with fast swimming goldfish. Fast swimmers are aggressive eaters at feedings.

Characteristics and Traits of Telescope Goldfish

How large does a Telescope goldfish get?

  • 8”

What is the lifespan of Telescope goldfish?

  • Pond environment: 10-15 years

Diet of Telescope Goldfish

What does a Telescope goldfish eat?

  • Pellets
  • Flake food
  • Live food (bloodworms, shrimp)
  • Fruits & vegetables

Tank Requirements for Telescope Goldfish

What size tank does a Telescope goldfish need?

  • Minimum: 20-30 gallons
  • Fish-to-tank Ratio is 1” of fish per 1 gallon of water

What should the water temperature be for a Telescope goldfish; and do I need to have a heater for the tank?

  • 65 - 72 degrees (F)
  • A heater is required to maintain water temperature.

Do I need to have an air stone (air pump) in my Telescope goldfish’s tank?

  • Yes, but avoid having one that is too powerful because Telescopes are slow swimmers and too much water movement will cause them to have trouble swimming.

Does a Telescope goldfish’s tank require a filtration system?

  • Yes, all goldfish should have a filtration system in their tank.
  • Be careful that your filtration system’s water intake is not too powerful for the Telescope because they are slow swimmers and too much movement in the water can be difficult for your Telescope to tolerate.

Special Care for the Telescope Goldfish

Do Telescopes require special care because of poor eyesight and swimming difficulty?

  • The tank must not have anything pointy or sharp because of the Telescope’s delicate eyes. Special care must be used when using decor or plants in the tank.


Street, R. 2002. "Carassius auratus" (On-line), Animal Diversity Web. Accessed November 13, 2018 at

CABI, 2018. Fallopia japonica. In: Invasive Species Compendium. Wallingford, UK: CAB International.

BBC News “Four Secrets Your Goldfish Is Hiding From You” By Jason G. Goldman21 October 2014

Aquatic Invaders of the Pacific Northwest; Carassius auratus auratus (Common Goldfish) Fish 423 Autumn 2014 By Martin Safer