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Telescope Goldfish

Carassius auratus

Also called Demekin, Telescope eye, Dragon eye (historic Chinese name)

VarietyShort profile

From China, developed in the early 1700s; later spread to Japan, Europe and the USA1

At a glance the quick version

Length10 to 25 cm1
Lifespan6 to 25 years12
Sizesmall
Striking globe-shaped eyes
Hardy and tolerant of a range of temperatures
Huge choice of colours
1

Looks how to spot one

Scaled, deep-bodied twin-tailed goldfish with protruding telescope eyes

A rounded, deep-bodied goldfish shaped much like a fantail, with long flowing fins and a double tail. Its big, globe-like eyes stand out on either side of the head. Fin length varies, from veiled forms to broad-tailed and short-finned types such as the 'China doll'.13

Coloursredorangeyellowred-and-whitecalicoblackblack-and-white (panda)chocolatebluelavenderkirinchocolate-and-bluemetallic, matte or nacreous scales1

Personality what they are like

Calm and peaceful. Its sight is limited, so it does best with other gentle, slower fancy goldfish such as bubble eyes and celestials rather than fast single-tailed goldfish.13

Daily activity how busy a day looks

Moderate. A steady swimmer that appreciates wide, open space and gentle flow.14

Grooming and care the hands-on bits

Needs a good filter, regular partial water changes with dechlorinated, temperature-matched water, and routine tests showing zero ammonia and nitrite. Choose smooth rocks and soft or silk plants to suit its prominent eyes.45

Home where they are happiest

Keep in a filtered aquarium, not a bowl. Aqueon suggests at least 40 litres (10 US gallons) per adult fancy goldfish, while the RSPCA advises at least 60 litres per goldfish, with wider tanks giving more stable water. Fancy goldfish are comfortable at about 20-23 °C (Aqueon gives 68-74 °F), and the RSPCA notes goldfish in general live at 10-21 °C without a heater. A pH of roughly 6.0-8.4 is fine (FishBase gives 6.0-8.0, Aqueon 7.0-8.4).546

Food basics what goes in the bowl

Omnivore. Offer a goldfish flake, granule or sinking pellet once or twice a day, only as much as is eaten in two to three minutes, with frozen or live foods as occasional treats. Give it time at feeding so it can find its share.56

Company who they like around

A sociable fish that likes company; FishBase suggests goldfish in groups of five or more. Ideal companions are other telescope, bubble eye and celestial goldfish.61

The story where it all began

Chinese breeders developed telescope-eyed goldfish, first called 'dragon eyes', in the early 1700s, though black forms are said to go back further. The type reached Japan, where it is called demekin, and later Europe and North America, arriving in the USA in the 1800s.1

Fun facts for the dinner table

  1. 1

    In Japan the telescope goldfish is called demekin.1

  2. 2

    Its original Chinese name was 'dragon eyes'.1

  3. 3

    Telescope fry hatch with normal-looking eyes, and the eye shape and colour develop as they grow.1

  4. 4

    In 1941 a Moscow aquarist bred a black telescope with orange-red eyes.1

  5. 5

    A telescope goldfish appeared on a Mozambique postage stamp in 2018.1

Recognised by the official bits

Taxonomy
Twin-tailed fancy goldfish variety with protruding eyes; the black form is called the Black Moor and the black-and-white form the Panda Moor1
IUCN Red List
The parent species Carassius auratus is assessed as Least Concern6

The care rhythm a typical week and year

A typical home-care rhythm for a Telescope Goldfish. A starting point, not a vet's advice.

Owner questions the things everyone asks

How often should I feed my Telescope Goldfish?

Feed your Telescope Goldfish once or twice a day, offering only as much food as it can eat in two to three minutes. This helps keep the water clean and your fish healthy. Furry Diary's starting plan suggests feeding daily.56 Pet Wiki plan

What does a Telescope Goldfish eat, and what should it never eat?

As an omnivore, it enjoys goldfish flakes, granules, or sinking pellets, with occasional frozen or live treats. Never feed it anything that could harm its delicate eyes, like sharp or large foods, and avoid overfeeding. For specific amounts, check the food label and ask your vet.56

How much space does a Telescope Goldfish need?

A filtered aquarium is a must, not a bowl. Aim for at least 40 to 60 litres per adult fancy goldfish, with wider tanks offering more stable water. This gives your fish room to swim and thrive.546

What temperature, light or water does a Telescope Goldfish need?

Keep the water at a comfortable 20-23°C (68-74°F) for fancy goldfish, though they can live in 10-21°C without a heater. A pH of 6.0-8.4 is fine, and always use dechlorinated, temperature-matched water for changes. Gentle lighting is best to avoid stressing its sensitive eyes.546

How often should I clean a Telescope Goldfish's home?

Furry Diary's starting plan suggests a weekly 25-30% water change, along with weekly glass cleaning and water testing. Rinse the filter monthly. Always use dechlorinated, temperature-matched water to keep your fish happy.45 Pet Wiki plan

Can a Telescope Goldfish live with others?

Yes, it's a sociable fish that enjoys company, ideally in groups of five or more. Choose gentle, slow companions like other telescopes, bubble eyes, or celestial goldfish, and avoid fast single-tailed types that might outcompete it for food.61

How long does a Telescope Goldfish live?

With proper care, your Telescope Goldfish can live between 6 and 25 years. A clean, spacious home and a good diet will help it reach its full lifespan.12

Can I handle a Telescope Goldfish?

It's best not to handle your Telescope Goldfish, as its protruding eyes are very delicate and easily injured. Always use a soft net if you need to move it, and keep handling to a minimum.13

Written from the sources on this page, a few checked guides (VCA, ASPCA, RSPCA) and Pet Wiki's own starting care plan. A friendly guide, not a vet's advice.

You might also like

Black MoorPanda MoorButterfly Tail GoldfishCelestial Eye GoldfishBubble Eye GoldfishFantail Goldfish

Where this comes from

Every fact on this page has a numbered source. Spotted an error? support@petwiki.app.

  1. Telescope (goldfish) - Wikipedia en.wikipedia.orgused for origin, history, names, body, colours, size, lifespan, fun facts
  2. Goldfish - Britannica britannica.comused for lifespan
  3. List of goldfish varieties - Wikipedia en.wikipedia.orgused for body, tankmates
  4. Fish environment - RSPCA rspca.org.ukused for tank size, filtration, water changes
  5. Goldfish Care Sheet - Aqueon aqueon.comused for temperature, tank size, diet
  6. Carassius auratus - FishBase fishbase.seused for pH, group size, diet, IUCN

Checked 2026-09-30. Text is written in our own words from these sources.