Telescope Goldfish

Demekin, Dragon Eye Goldfish, Globe Eye Goldfish

Family: Cyprinidae TTelescope Goldfish, Globe Eye Goldfish, Demekin, Dragon Eye GoldfishCalico Telescope GoldfishCarassius auratus auratusPhoto © Animal-World: Courtesy Tammy
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hi, i was brought 2 telescope eye goldfish the other day in a bowl.. i know thats waayyyy too small for them but the guy in the shop said they'd be fine. I'm... (more)  Amy Bannister

The Telescope Goldfish is a bizarre looking fish, with eyes perched on stalks sticking out from its head!

The eyes are a most curious characteristic of the Telescope Goldfish. Their large eyes are set on top of long telescope or cone-like stalks mounted on the sides of its head. On some fish these stalks can extend out as far as 3/4 of an inch (19 - 20 cm), but they don't really start to protrude until these fish are about 6 months old.

It is believed the Telescope Goldfish were first developed in China in the early 1700's and were called the Dragon Eye Goldfish or Dragonfish. Later in that century they were produced in Japan and were given the name Demekin, which the Japanese still call them today.

A basic Telescope Goldfish is one of the more rounded or egg-shaped fancy gold fish. It is very similar to the Fantail Goldfish with the exception of its eyes, and being slightly smaller. The body is short and stubby, the head is very wide, and they have a split caudal fin (tail fin) that is moderate in length and slightly forked. Today they are also available with long flowing fins and a couple other tail fin styles: veil tail, broadtail, and butterfly tail.

There are many different colors in both metallic and nacreous scale types, but seldom in a matte scale type. These include solids of red, blue, chocolate, or white; tri-colored and calico; and bi-colored versions in red/white and black/white. The bi-colored black/white version is affectionately known as the Panda Telescope Goldfish and there is a unique chocolate version with orange pompoms. The well known and very popular Black Moor Goldfish is basically a black version of the Telescope Goldfish though its eyes don't protrude quite as far.

Like the Black Moor the Telescope Goldfish have the ability to live at colder temperatures, but unlike their cousin they are not considered a good beginner fish. This is not because they lack general hardiness, but rather because of their more extremely telescopic eyes. Their eyes cause them to have poor vision so they are not a good competitor for food, and their eyes are subject to injury and infection. These fish will thrive best housed with the other similarly handicapped including the Black Moor and the less hardy Bubble Eye Goldfish Lionhead Goldfish, and Celestial Goldfish.

For more goldfish information, see:
Goldfish Care: Fancy Goldfish and Goldfish Diseases


Geographic Distribution
Carassius auratus auratus
Data provided by FishBase.org
  • Kingdom: Animalia
  • Phylum: Chordata
  • Class: Actinopterygii
  • Order: Cypriniformes
  • Family: Cyprinidae
  • Genus: Carassius
  • Species: auratus auratus
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Telescope Goldfish - Quick Aquarium Care
  • Size of fish - inches: 8.0 inches (20.32 cm)
  • Minimum Tank Size: 10 gal (38 L)
  • Temperament: Peaceful
  • Aquarium Hardiness: Moderately hardy
  • Temperature: 65.0 to 72.0° F (18.3 to 22.2° C)
  • Aquarist Experience Level: Intermediate
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Habitat: Distribution / Background

The goldfish of today are descendants of a wild carp fish, known as the Prussian Carp, Silver Prussian carp, or Gibel Carp Carassius gibelio (syn: Carassius auratus gibelio) which was described by Bloch in 1782. These wild carp originated in Asia; Central Asia (siberia). They inhabit the slow moving and stagnant waters of rivers, lakes, ponds, and ditches feeding on plants, detritus, small crustaceans, and insects. For many years it was believed that goldfish had originated from the Crucian Carp or Golden Carp Carassius auratus auratus described by Linnaeus in 1758, but more recent research is pointing toward the former.

Goldfish were originally developed in China, but by the 1500's goldfish were traded to Japan, to Europe in the 1600's, and to America by the 1800's. The majority of the fancy goldfish were being developed by Oriental breeders. The results of this centuries long endeavor is the wonderful goldfish colors and forms we see today. Today domesticated goldfish are distributed world-wide.

The Telescope Goldfish is also known as the Demekin, Dragon Eye Goldfish, and Globe Eye Goldfish. It was believed to be developed in China in the early 1700's where it was known as the Dragon Eyes or the Dragonfish. In the later part of the 1700's it was produced in Japan where it is known as the Demekin. The Black Moor is still referred to as the Dragon Eye Goldfish as well as the Black Demekin. Today there are more than 125 captive bred fancy gold fish varieties.

  • Scientific Name: Carassius auratus auratus
  • Social Grouping: Groups
  • IUCN Red List: NE - Not Evaluated or not listed - There are no wild populations of this captive bred variety.

Description

The Telescope Goldfish is an egg-shaped variety of goldfish. Other than its eyes, and being slightly smaller, a basic Telescope Goldfish is very similar to the Fantail Goldfish. The body is short and stubby, the head is very wide, and they have a split caudal fin (tail fin) that is moderate in length and slightly forked.

Telescope Goldfish will generally reach up to about 5  inches (12.7 cm), though they have been known to grow much larger in many aquarists tanks. With optimal conditions they can reach a length of up to 8 inches (20.32 cm). The average goldfish lifespan is 10 – 15 years, though living 20 years or more is not uncommon in well maintained goldfish aquariums and ponds.

Their large eyes are set on top of long telescope or cone-like stalks mounted on the sides of its head. On some fish these stalks can extend out as far as 3/4 of an inch (19 - 20 cm), but they don't really start to protrude until these fish are about 6 months old. Today the Telescope Goldfish are also available with long flowing fins and a couple other tail fin styles: veil tail, broadtail, and butterfly.

There are many different colors in both metallic and nacreous scale types, but seldom in a matte scale type. These include solids of red, blue, chocolate, or white; tri-colored and calico; and bi-colored fish in red/white and black/white.

The bi-colored black/white version is affectionately known as the Panda Telescope Goldfish and there is a unique chocolate version with orange pompoms. The well known, and very popular Black Moor Goldfish is basically a black version of the Telescope Goldfish though its eyes don't protrude quite as far.

  • Size of fish - inches: 8.0 inches (20.32 cm) - Telescope Goldfish rarely exceed five inches in the home aquarium, however given optimal conditions they can grow up to eight inches in length.
  • Lifespan: 15 years - The average goldfish lifespan is 10 – 15 years, but they have been known to live 20 years of more when well maintained.

Fish Keeping Difficulty

The Telescope Goldfish are not considered a good beginner fish. This is not because they lack general hardiness, but rather because of their more extremely telescopic eyes. Besides causing them to have poor vision, Their eyes, besides causing them to have poor vision, are subject to injury and infection. They are very undemanding of water quality and temperature.

They can do well in a goldfish aquarium or even a pond if the environment is safe, well maintained, and has tank mates that are not competitive. When it comes to feeding, they will not thrive well with fast competitive tank mates.

Many people will keep goldfish in an aquarium with no heater or filtration, but for the best success provide them the same filtration, especially biological filtration, that other aquarium residents enjoy. Be careful when netting these fish, as their eyes are easily damaged. When it comes to feeding, they will not thrive well with fast competitive tank mates.

  • Aquarium Hardiness: Moderately hardy
  • Aquarist Experience Level: Intermediate

Foods and Feeding

Since they are omnivorous, the Telescope Goldfish will generally eat all kinds of fresh, frozen, and flake foods. To keep a good balance give them a high quality flake food everyday. Feed brine shrimp (either live or frozen), blood worms, Daphnia, or tubifex worms as a treat. It is usually better to feed freeze-dried foods as opposed to live foods to avoid parasites and bacterial infections that could be present in live foods. Due to the protruding eyes they have poor vision and a harder time seeing their food, so need extra time to feed.

  • Diet Type: Omnivore
  • Flake Food: Yes
  • Tablet Pellet: Yes
  • Live foods (fishes, shrimps, worms): Some of Diet
  • Vegetable Food: Some of Diet
  • Meaty Food: Some of Diet
  • Feeding Frequency: Several feedings per day - This fish has poor vision and is a poor swimmer and as such might easily be outcompeted for food by swifter moving tankmates.

Aquarium Care

Regular weekly water changes of 1/4 to 1/3 is strongly recommended to keep these fish healthy. Snails can be added as they reduce the algae in the tank, helping to keep it clean.

  • Water Changes: Weekly

Aquarium Setup

Setting up a goldfish aquarium in a manner that will keep your fish happy and healthy is the first step to success. The shape and size of the goldfish aquarium is important and depends upon the number of fish you are going to keep. These fish need a lot of oxygen and produce a lot of waste. Good filtration, especially biological filtration, is very helpful in maintaining the water quality of the aquarium. Filtration systems remove much of the detritus, excess foods and waste. This in turn helps to keep the tank clean and maintain the general health of the goldfish.

  • Tank parameters to consider when choosing a goldfish aquarium:
    • Tank size
      Ten gallons is the absolute minimum required to house a Telescope Goldfish. It's best to start with a 20 - 30 gallon tank for your first goldfish and then increase the size of the tank by 10 gallons for each additional goldfish. Providing a large amount of water per fish will help dilute the amount of waste and reduce the number of water changes needed.
    • Tank Shape
      Always provide the maximum amount of surface area. A large surface area of water will help minimize goldfish suffering from an oxygen shortage. Surface area is determined by the shape of the tank. For example an elongated tank offers more surface area (and oxygen) than a tall tank. In an oval or round shaped tank the middle offers more surface area than filling it to the top.
    • Number of fish
      For juveniles a general rule of thumb is 1 inch of fish (2.54 cm) per 1 gallon of water. But this rule only applies to young fish and is not adequate as they grow. Larger gold fish consume much more oxygen than young fish so maintaining this formula for growing fish will stunt them, and can contribute to disease and even death.
    • Fish size and growth
      To allow for proper growth, either buy fewer fish than the maximum number or be prepared to get a larger tank. To prevent stunted growth and other health problems, don't overstocking the aquarium.

Goldfish are a cold water fish and will do best at temperatures between 65 - 72° F (18°- 22° C). The Telescope Goldfish can tolerate temperatures a few degrees above freezing, as long as the cooling drops only a few degrees a day. A quick temperature drop can kill them, so if you live in a very cold climate a heater is advisable

Provide a gravel substrate to help create a natural and comfortable environment for your fish. You can add some decor, but keep in mind that the eyes of the Telescope Goldfish are a handicap. These fish have very poor vision so make sure that all ornamentation is smooth with no protruding points or sharp edges. Smooth rocks or driftwood, should be used sparingly if at all. Aquarium plants would be the best choice of aquarium decor for goldfish, but unfortunately these fish are diggers. Consequently live plants may be uprooted. Artificial plants make a good substitute and silk plants are safer than plastic ones.

Most aquariums come with a cover that includes lighting. A cover for the tank is desirable as it reduces evaporation and though they are not prone to jumping, on occasion some gold fish will jump out. Lighting is not essential for goldfish, but does make the aquarium a nice show piece and lighting will help if you have live plants.

Goldfish are freshwater fish, but they have some tolerance for slightly brackish water. The salinity level for C. auratus must be kept low, below 10% with a specific gravity of less than 1.002.

  • Minimum Tank Size: 10 gal (38 L) - Ten gallons is the absolute minimum required to house this fish. It has high oxygen requirements, produces a lot of waste. It will have very stunted growth if it is kept in a smaller aquarium.
  • Suitable for Nano Tank: Sometimes - A Nano tank is fine as long as it is 10 gallons or more.
  • Substrate Type: Any - A medium sized gravel works best.
  • Lighting Needs: Moderate - normal lighting
  • Temperature: 65.0 to 72.0° F (18.3 to 22.2° C)
  • Range ph: 6.0-8.0
  • Hardness Range: 5 - 19 dGH
  • Brackish: Sometimes - The salinity for C. auratus must be kept below 10%, a specific gravity of less than 1.002.
  • Water Movement: Moderate
  • Water Region: All - These fish will swim in all areas of the aquarium.

Social Behaviors

Goldfish are very social animals and thrive in a community. Not only are they a great community fish but they are great scavengers as well. The Telescope Goldfish, along with the Black Moor Goldfish, Bubble Eye Goldfish, and the Celestial Goldfish, are all visually handicapped. They cannot readily compete for food with other types of goldfish so may not fare well if housed with them, but they will do well housed together. Goldfish are great scavengers, so it is really not necessary to add other scavengers or other bottom feeders to the aquarium when you have goldfish.

  • Venomous: No
  • Temperament: Peaceful
  • Compatible with:
    • Same species - conspecifics: Yes
    • Peaceful fish (): Safe
    • Semi-Aggressive (): Threat
    • Shrimps, Crabs, Snails: Safe - not aggressive
    • Plants: Threat - Goldfish will eat many kinds of aquatic plants, and their constant search for food can end up uprooting plants that they don't eat.

Sex: Sexual differences

During the breeding season the male has white prickles, called breeding tubercles, on its gill covers and head. Seen from above a female will have a fatter appearance when she is carrying eggs. It is impossible to sex Goldfish when they are young and not in breeding season, but generally the male is smaller and more slender than the female.

Breeding / Reproduction

Telescope Goldfish are egg layers that spawn readily in the right conditions. See Breeding Freshwater Fish - Goldfish for more information on breeding Goldfish.

  • Ease of Breeding: Moderate

Fish Diseases

Goldfish are subject to the same diseases as tropical fish. A couple of the more common problems are Ich, Swim Bladder Disease, and external parasites including flukes, lice and anchor worms. For more in-depth information about goldfish diseases and illnesses, see: Goldfish Care; Fancy Goldfish and Goldfish Diseases.

Availability

The Telescope Goldfish is readily available in fish stores and on-line, and is fairly inexpensive.

References

Author: David Brough CFS
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Lastest Animal Stories on Telescope Goldfish


Amy Bannister - 2014-09-09
hi, i was brought 2 telescope eye goldfish the other day in a bowl.. i know thats waayyyy too small for them but the guy in the shop said they'd be fine. I'm looking to upsize for them but really can't stretch to a 10 or 20 gallon tank at the moment. they are only about an inch ling each. will a 15L or 20L be enough for the time being, with a filter and airstone put into it. also could you suggest the best food for them a few people have said sinking pellets but they don't seem to be finding them very well

Reply
Emilly - 2011-09-10
Hi I got my telescopic eyed Goldfish and her name is Bow, last night just before I went to bed I checked on her and she seemed to be resting in the bottom corner? Was she just resting or sleeping or is something wrong with her ..... she seems to be fine when I feed her and then she is fine ..... I hope she is okay?

  • Clarice Brough - 2011-09-12
    Well, if she seems fine most of the time, she probably is fine. But I would keep and eye on her just to be sure. Staying in a corner all the time would indicate something's wrong, like the water quality is bad, or another fish picking on her.
  • Anonymous - 2013-06-26
    I have a similar problem with my little fish, was slim like a shark, now has a big belly, rests in the corner. We have had our horn snail laying eggs and I think little fish has eaten some! I'm really worried about my little fish. Is there anything I can do? I changed the water and two days later he has a big belly and resting on the bottom. It takes little gulps at the surface, but not eaten food!
  • Anonymous - 2013-07-07
    Your little fishy may have swallowed some air when eating food, considering he/she has a big tummy. You should feed your fish frozen peas, not flakes or pellets, which may make the fish's stomach fill with air. Hope I helped! =)
  • Gary - 2013-08-11
    Hi, I have had a few globeyes and 1 has died. My 1st fish 'Horatio' had his problems at the start but he got through them. With regards to your fish resting on the bottom, they do rest from time to time and do sleep for a while, so don't be worried about that. The fish's belly will grow large due to its breed. Make sure the water quality is good and do regular changes with the recommended solutions.
  • Anonymous - 2014-06-03
    Hi, I have the same problem too I think. My goldfish is fine most of the time but when I get home from work it's in the corner. It's not fat or anything though.
  • John - 2014-07-31
    I have the same problem but they don't rest in the corner they rest at the bottom is there something I should be worried about and yes I have 2
Reply
Brenda - 2014-07-13
I have two telescope Goldfish & was wondering if I can use well water & what solutions are best??

  • Clarice Brough - 2014-07-22
    The advantage of using your own well water is there won't be any chlorine or chloramine, so it can work well without adding the typical water conditioners. However I would check the hardness range and make sure it's between 5 - 19 dGH. If higher or lower, you may need to adjust it.
Reply
ted - 2013-11-09
I have had a telescope eye goldfish for about 9 days now and it seems to have grown a penis, can anybody help me on this? Is this normal? It doesn't seem right.

  • Clarice Brough - 2013-12-10
    Goldfish are susceptible to anchor worms, that may be the problem.
Reply
bettybloop - 2011-11-15
I wanted to name our little friend xray because you can see right thru his eye and out the other side. Cool little buddy. bloop bloop bloop... :) hunnys daughter named him col. sanders.? these fish are cool!! We're down to 2 (had 4) that are doing very well. New tank and just learning...it's not quite as simple as we thought it would be. Buy tank, add water, add fish. Learning that there's a little more to it than that. Sorry lenny (fish 1) and wigga (fish 2). And RIP Red. (poor little betta..learning curve..oops. and where can we buy a panda telescope? Anybody know? :) bloop bloop bloop...

  • Charlie Roche - 2011-11-17
    X-Ray is a great name.
Reply