In the exciting world of aquaristics, the telescope fish It is positioned as one of the most unique and admired cold water species. This variety of Golden carp (goldfish) is notable for its striking bulging eyes and captivating appearance, receiving multiple names depending on the region: Demekin, Dragon Eyes, Moorish Goldfish, or Telescope Goldfish. Thanks to its unique physical features, friendly behavior, and wide range of variants, the telescope goldfish is a favorite in home aquariums around the world.
In this extensive and detailed article you will discover everything you need to know about The care, characteristics, reproduction, types, compatibility, feeding, and diseases of the telescope fish, incorporating all the most specialized and up-to-date information so you can keep these wonderful, bulging-eyed fish happy and healthy.
Origin and Taxonomy of the Telescope Fish
El telescope fish belongs to the genus carassius within the family CyprinidaeIts scientific name is Carassius auratus auratus, a variety selected and artificially bred from the Chinese crucian carp. The selection and breeding of the telescope fish began in China (where it is known as "Dragon Eyes") and was later introduced and refined in Japan under the name "Demekin." Since the development of the first varieties, selective breeding has resulted in a great diversity of shapes, colors, and subtypes over the centuries.
- Kingdom: Animalia
- Division: Chordata
- Class: Actinopterygii
- Order: cypriniformes
- Family: Cyprinidae
- Gender: carassius
- Common name: Telescope fish, telescope goldfish, telescopic-eyed goldfish
Today telescope fish It is distributed worldwide thanks to the aquarium hobby, and continues to be the subject of new varieties and genetic improvements in China, Japan and other specialized countries.
Physical and Morphological Characteristics
The most notable feature of telescope fish It is, without a doubt, the form of its prominent eyes, which protrude noticeably from the head, reaching up to 20 mm in diameter in some specimens. The eyes can be rounded, conical, or slightly globular, and are covered by a transparent membrane. This morphology is the result of selective breeding and, although it gives a spectacular appearance, significantly reduces the animal's visual capacity. fry They are born with normal eyes, which begin to protrude around the first month of life and continue to develop progressively.
The body of the telescope fish is short, robust and ovoid in shape. It usually measures between 15 and 20 cm in aquarium, being able to reach 30 cm in exceptional conditions. Their weight can reach up to 1,5 kg, although this is more common in pond specimens or exhibition specimens. The life expectancy of these fish can vary significantly depending on the quality of care, commonly falling between 5 and 10 years, although there are records of specimens that have lived up to 15 and even 25 years.
- Fins: The caudal fin is long, flowing, and fan-shaped, with rounded edges. The dorsal and pectoral fins are well-proportioned and usually blend with the body line.
- Coloration: It comes in a wide variety of intense colors, including black, orange, yellow, red, white, and bicolor combinations (panda coloration, red-black, red-white, yellow-black). The most intensely colored specimens with well-developed ocular symmetry are the most sought-after.
- Swimming difficulty: Its compact body and limited vision make it a relatively slow and clumsy swimmer, which must be taken into account for its well-being in the aquarium.
Selective breeding has produced specimens with fin varieties (veil type), shapes and colors unique, increasing their ornamental appeal in the home aquarium.
Behavior and Temperament
El telescope fish It is sociable, docile, and gregarious. It prefers to live in groups with other slow-moving, peaceful goldfish, with whom it usually interacts harmoniously. It shows great curiosity, exploring the bottom of the aquarium, removing stones, and gently nibbling on plants or decorations. However, due to its poor vision, it is prone to colliding with other fish, plants, and decorative objects, so it is essential to avoid ornamentation with sharp edges.
It is not territorial or aggressive, although coexistence with small fish (fry) or fast-swimming species with a competitive character should be avoided, as it could present problems accessing food and may not perceive their tank mates well.
- Optimal group: Ideally, keep a minimum of three specimens to encourage natural behavior and reduce stress.
- Typical behaviors: Searching and digging substrate, pushing decoration, nibbling plants.
Feeding the Telescope Fish
El telescope fish It is omnivorous with a preference for a varied and balanced diet, which makes it easier to care for but requires some attention given its tendency to supercharging and digestive problems. The dietary basis should be composed of specific commercial food for goldfish in the form of sinking pellets, since floating foods can encourage air intake and development swim bladder disorders.
- Commercial foods: Pellets, good quality flakes formulated for goldfish.
- Live and freeze-dried foods: Artemia, daphnia, mosquito larvae, grindal worms, tubifex.
- Plant component: It is recommended to offer cooked or blanched vegetables such as peas (without skin), spinach, zucchini, or romaine lettuce two or three times a week, which promote digestion and prevent constipation.
- Frequency and quantity: Feed 2 to 3 times a day in small amounts that they can consume in less than 2 minutes, avoiding debris in the aquarium. supercharging is one of the main health risks.
- Foods to avoid: Poor quality feed, very fatty or high protein foods (in moderation), bread, biscuits, rice, human food waste.
The occasional contribution of specific supplements (such as pumpkin or carrot flour) can enhance the coloration, as current studies have shown.
Care and Characteristics of the Aquarium for the Telescope Fish
To ensure the health and well-being of the telescope fish, it is essential to recreate an environment that is as safe and comfortable as possible:
- Aquarium size: Minimum of 75 liters for a juvenile specimen; add an additional 40 liters for each additional adult fish. An aquarium at least 120 cm long is ideal for keeping a group.
- Aquarium shape: Avoid round tanks, as they hinder gas exchange. Prefer long, wide aquariums.
- Substratum: Fine sand or soft gravel without edges so they can dig without injury.
- Decoration: Rounded elements, without points or rough edges. Well-seasoned trunks and smooth rocks.
- Plants: Natural and durable (Anubias, Java Fern) or artificial silk. Avoid hard, pointy plastic.
- Oxygenation and filtration: A powerful filtration system (preferably external) but with a gentle flow to minimize movement. Add bubble diffusers for extra oxygen.
- Water temperature: Between 18 and 24 ° C, tolerating occasional variations from 10°C. They are cold water fish, sensitive to sudden changes.
- pH: Between 7,0 and 7,5.
- Hardness: 10-15 dGH.
- Water changes: Partials of 30% weekly and ammonia control (NH3 0 ppm) and nitrates (NO3 < 20 ppm) to maintain excellent quality.
- Lighting: Moderate, never intense or direct, as telescope fish are sensitive to light and can develop fungus or eye lesions from overexposure.
- Reproduction container: For spawning, it is preferable to use an aquarium of more than 80 liters or even a pond, replicating the natural environment and with plants such as Cabomba or Elodea where the eggs can adhere.
Types and Varieties of Telescope Fish
The great diversity of telescope fish It arises from genetic selection and captive breeding. There are several varieties, each with distinctive traits in terms of coloration, body shape, fin length, and eye development.
Black Moor Telescope Fish
- Color: Intense velvety black, although many specimens may develop orange or rust tones on the belly with age.
- Longevity: Between 6 and 25 years in optimal conditions.
- Resistance: It is able to adapt well to different parameters and is very popular among beginners.
Panda Telescope Fish
- Color: Bicolor black and white on the body and fins, with prominent eyes.
- Variability: It may lose its coloration with age and turn orange or white.
- Condition: It is a strictly cold water variety.
White Telescope Fish
- Appearance: Similar to the classic goldfish, but pure white.
- Size: It can reach up to 15 cm in length.
- Compatibility: It tolerates living with other slow and peaceful varieties.
Celestial Eye Telescope Fish
- Unique feature: Large, bulging eyes facing upwards, also called "Chotengan".
- Difficulty: It requires stricter care, especially regarding water quality.
Bubble-Eye Telescope Fish
- Characteristic: Fluid-filled sacs under the eyes, very sensitive and delicate.
- Driving: It requires maximum caution in the decoration and handling of the aquarium.
There are also variants in gold tones, calico (multicolor), red-black and other combinations, which further increases its ornamental appeal.
Reproduction of the Telescope Fish
El telescope fish It is oviparous and reaches sexual maturity between its first and second year of life, depending on its size and developmental conditions. The reproductive process is often emulated in aquariums by inducing spawning:
- Natural induction: Lowering the water temperature to 11°C and gradually increasing it to around 20–23°C promotes spawning.
- Synthetic hormones: In specialized hatcheries, hormones can be used to enhance laying (advanced technique, experts only).
- Courtship: The male follows and pushes the female against plants until she releases eggs. The process can take several hours.
- Put: The female lays between 300 and 2.000 adhesive eggs that attach to vegetation or decoration.
- Separation of parents: After laying, it is advisable to separate the adults to prevent them from eating the eggs.
- Hatching: The eggs hatch between 45 and 72 hours after laying, depending on the temperature. The fry initially feed on zooplankton and then live food (worms, brine shrimp).
Sexual differentiation is often difficult, but during the breeding season, males display reproductive tubercles on the head and fins, a thinner abdomen, and chasing behavior, while females display a bulging abdomen and are chased.
Compatibility with Other Fish
For his slow swimming and vulnerable vision, the telescope fish They should only be kept with equally calm and slow-moving species. Fancy goldfish such as:
- Other telescopes
- Fantail
- ryukin
- at the rate
- Bubble Eye
- Celestial Eye
- Corydoras
- Chinese neon fish
Absolutely avoid coexistence with common goldfish, comets, shubunkins, aggressive fish (barbs, oscars), fast swimmers or species that bite fins.These companions may snatch their food and injure their delicate eyes or fins.
Specific Eye and Health Care
The prominent eyes The telescope fish's most distinctive feature is its weakness:
- Limited vision: It makes eating and moving difficult, promoting bumps and injuries.
- Trauma proneness: Avoid sharp decorations, rough objects, and competitive partners.
- Eye infections: They can develop Popeye (bacterial eye swelling), cloudy eyes (from poor diet or dirty water), and eye shrinkage from chronic infections.
- Prevention: Maintain impeccable water quality, balanced nutrition, and a safe environment.
Common Diseases and Treatment
The most frequent diseases They affect especially when the aquarium parameters are not optimal:
- Dropsy: Kidney infection, swelling, and scaling. Fatal if not treated promptly.
- Tuberculosis de peces: Causes hollow belly, lethargy, deformities, clipped fins.
- Ich (White Spot Disease): Appearance of white spots caused by protozoa on the skin, fins and gills.
- Cloudy eye: Ocular cloudiness, due to poor water quality or nutritional deficiencies.
- Constipation: Bloating and lack of appetite, usually due to poor nutrition. Fasting the fish and feeding them live food will correct the problem.
- Swim bladder disease: Abnormal buoyancy, resulting from constipation, infections or physical malformations.
- External parasites: Trematodes and fish lice (Argulus), can be treated with specific medications such as trichlorfon.
Key measures: Isolate sick specimens in a hospital aquarium, maintain frequent water changes, and resort to veterinary-diagnosed treatments when necessary.
The price of telescope fish usually oscillates between 2,90 and 5 € depending on variety and quality.
El telescope fish It's a fascinating yet demanding specimen. To fully enjoy its impressive appearance and personality, a spacious aquarium, specific water quality care, a balanced diet, and properly selected tank mates are essential. Preventing eye diseases and addressing its specific needs can make this goldfish the undisputed star of your coldwater aquarium for many years.
