Goldfish with Big Eyes: A Comprehensive Guide to Bubble Eye Varieties

Goldfish are popular pets known for their beautiful colors and various shapes. One fascinating feature of some goldfish breeds is their large, protruding eyes. While big eyes are a normal characteristic for certain types of goldfish, in some instances, enlarged eyes can indicate health issues. In this article, we will discuss both the fascinating big-eyed goldfish breeds and the potential risks associated with eye swelling.

Telescope eye goldfish, black moor goldfish, and celestial-eyed fancy goldfish are some of the breeds with naturally big eyes. These unique features make these breeds highly sought after by aquarists and goldfish enthusiasts alike. Each type exhibits distinct traits and characteristics, contributing to the diverse world of goldfish aesthetics.

On the other hand, some goldfish may experience a condition called “pop eye” or exophthalmia, which causes the eyes to swell abnormally. This can be caused by trauma or other underlying issues, and requires prompt attention to prevent complications such as blindness. We will explore the causes, symptoms, and treatments for pop eye in goldfish throughout this article.

Understanding Goldfish with Big Eyes

Telescope Goldfish

Telescope Goldfish (Carassius auratus), also known as Demekin, Dragon Eye Goldfish, or Globe Eye Goldfish, belong to the family Cyprinidae. They are a type of fancy goldfish, characterized by their large, protruding eyes. While their big eyes may seem intriguing, they serve no functional purpose and can result in impaired vision for the fish.

These goldfish have an egg-shaped body and typically have deep, rounded bodies with a pronounced dorsal fin. The scales of the telescope goldfish can be either metallic or nacreous, and they can display various colors, including calico, orange, and black.

Originating in Asia, specifically Japan and China, telescope goldfish have been selectively bred for centuries. As a result, various types of big-eyed goldfish with unique features, such as the Black Moor and Celestial Eye, have been developed.

Types of Big-Eyed Goldfish

Several types of big-eyed goldfish have been selectively bred, with some of the most popular being:

  • Black Moor Goldfish: This variety has a deep, round body, similar to the telescope goldfish. However, they are typically all-black or dark-colored with a velvety appearance. The Black Moor Goldfish has large, protruding eyes and its vision is generally better than that of other telescope varieties.
Black Moor Goldfish
  • Celestial Eye Goldfish: Distinguished by their upward-facing eyes that protrude from their heads, Celestial Eye Goldfish have eyes as large as their entire heads. Contrary to the telescope goldfish, their bodies are smaller and more similar to those of common goldfish.
Celestial Eye Goldfish
  • Lionhead Goldfish: Featuring a prominent “hood,” or fleshy growth, on their heads, Lionhead Goldfish have large, round eyes that are close together. These goldfish also have an egg-shaped body and lack a dorsal fin.
Lionhead Goldfish
  • Oranda Goldfish: Orandas have a distinct “wen,” or fleshy cap, on their heads, in addition to large, round eyes. Their bodies are deep and round, and they come in various colors, such as red, white, calico, and even chocolate.
Oranda Goldfish
  • Ryukin Goldfish: Ryukins have a humped back, which is more pronounced than other types of fancy goldfish. Their eyes are large, though not as protruding as those of the telescope goldfish.
Ryukin Goldfish
  • Pearlscale Goldfish: Known for their unique, pearl-like scales, Pearlscale Goldfish have round, protruding eyes and a round body. Their appearance makes them a popular choice among goldfish enthusiasts.
Pearlscale Goldfish

Goldfish with big eyes are captivating, yet require proper care and attention. Each type has its own specific requirements for optimal health and living conditions. It’s crucial for goldfish owners to research and understand these needs for the well-being of their big-eyed aquatic friends.

Physical Features and Characteristics


Goldfish with big eyes, such as the Celestial Eye and Telescope Eyed Fancy Goldfish, have a unique set of physical features. The large, protruding eyes result from a condition called exophthalmia, which is caused by tissue fluid leaking into the area behind the eyeball, leading to increased pressure and eye enlargement. This can make them more prone to eye injury.


These goldfish have a variety of fins, including the dorsal fin, caudal fin, and pectoral fin. The Bubble Eye goldfish, however, lack a dorsal fin, resulting in a completely smooth back. This absence of fin can cause swimming issues, but they compensate with a double tail, splitting the caudal fin into four points. Many goldfish with big eyes also have long, flowing fins which further define their graceful appearance.

Body Shape

The body shape of goldfish with big eyes varies between breeds. Some have a medium to short body, while others have a more rounded, chubby shape. The latter can cause slower swimming due to the combination of poor vision and a less streamlined body.

Scales and Patterns

Big-eyed goldfish have a variety of scale colors and patterns, making them visually appealing for aquarium enthusiasts. The scales can be metallic, matte, or nacreous, offering a diverse range of appearances. Patterns can include solid colors, calico, and bi-color combinations, adding to the uniqueness of each fish.

In summary, big-eyed goldfish possess a distinctive set of physical features and characteristics that set them apart from other goldfish types. Their protruding eyes, diverse fin types, varied body shape, and colorful scales and patterns contribute to their popularity and beauty in aquariums.

Caring for Goldfish with Big Eyes

Tank Requirements

When setting up a tank for goldfish with big eyes, such as Telescope Goldfish, it’s important to select a proper tank size. A minimum of 20 gallons per fish is recommended, with an additional 10 gallons per additional fish. This will help provide adequate space for your goldfish to grow and thrive.

Ensure the tank has a well-functioning filtration system, as these goldfish are sensitive to poor water quality. Avoid sharp or hard decorations, as these can injure their delicate eyes. Instead, opt for live plants or soft silk plants that will not harm your fish.

Water Quality

Maintaining proper water quality is crucial for the health of your goldfish with big eyes. Conduct regular water changes, replacing 25-30% of the freshwater in the tank every week. Test the water regularly to ensure it has the correct pH level, which should be between 7.0 and 8.0.

Monitor the temperature of the tank, maintaining it between 65-72°F. This range is suitable for most big-eyed goldfish varieties. It’s crucial to install a reliable heater and thermometer to maintain a consistent temperature in the tank.

Feeding and Nutrition

Goldfish with big eyes have poor eyesight, so providing an appropriate diet is critical. Feed them a high-quality pellet or flake food formulated for goldfish, ensuring they can locate the food easily. Offer vegetables, such as blanched spinach or lettuce, as supplemental nutrition.

Feed your goldfish 1-2 times daily, providing only what they can consume within a few minutes. Overfeeding can lead to water quality issues and increased risk of swim bladder infections.

Common Health Issues

Big-eyed goldfish are susceptible to a range of health issues, including infections and eye-related problems. Some common issues include:

  • Exophthalmia (Popeye): This is the swelling of the eye caused by tissue fluid leakage. Treatment may include antibiotics or finding and addressing the cause of the condition.
  • Swim Bladder Infections: These can result from overfeeding or poor water quality. Improve the water conditions and reduce feedings to help resolve this issue.

Always keep a close eye on your goldfish’s health and consult an expert or veterinarian if you suspect any issues. A well-maintained tank with proper water quality, filtration, and nutrition can help prevent many health problems in goldfish with big eyes.

Treating Health Issues in Big-Eyed Goldfish

Exophthalmia (Pop Eye)

Exophthalmia, also known as pop eye, is a condition where the eye of the goldfish is swollen and protrudes abnormally from its socket. It occurs when tissue fluid leaks into the region behind the eyeball, causing increased pressure inside the eye socket. To treat pop eye in goldfish, you must first identify the cause of the condition. If an infection is responsible, move the affected fish to a quarantine tank and administer antibiotics if necessary.

Bacterial Infections

Bacterial infections can cause various symptoms in goldfish with big eyes, such as lack of appetite, aggressiveness, hiding behavior, color changes, and skin growths. If you suspect a bacterial infection, you should:

  • Move the affected goldfish to a quarantine tank
  • Perform regular water changes to maintain optimal water quality
  • Administer broad-spectrum antibiotics and anti-inflammatory medication

Swim Bladder Issues

Swim bladder issues are common in big-eyed goldfish, such as bubble eye goldfish, due to their unique body shapes. These issues can cause poor balance and difficulty swimming. To treat swim bladder problems, try the following:

  • Ensure proper water quality and perform regular water changes
  • Feed the goldfish a varied diet, including foods that are easy to digest
  • Consider feeding the fish peas, as this can help alleviate some swim bladder issues

Injuries and Wounds

Big-eyed goldfish may sustain injuries to their eyes due to their protruding nature. To treat injuries and wounds in big-eyed goldfish:

  • Move the injured fish to a quarantine tank
  • Maintain optimal water quality by performing regular water changes
  • Treat the water with a safe, aquarium-approved antiseptic to prevent infection

Choosing and Buying Big-Eyed Goldfish

Suitable Breeds for Beginners

If you’re a beginner in the fish hobbyist world, selecting the right big-eyed goldfish breed is essential. Here are three popular big-eyed goldfish breeds suitable for beginners:

  1. Telescope Eye Goldfish: Also known as Demekin or Dragon Eye Goldfish, this breed is famous for its large, protruding eyes and comes in various colors like red, orange, yellow, white, and black.
  2. Butterfly Telescope Goldfish: This breed has a similar appearance to the Telescope Eye Goldfish but features a unique butterfly-like tail shape.
  3. Panda Telescope Goldfish: This attractive breed is characterized by its black and white color pattern, resembling a panda, and is a variant of the Telescope Eye Goldfish.

Selecting Healthy Fish

When choosing big-eyed goldfish, it’s crucial to select healthy fish to ensure a successful aquarium experience. Here are some tips to help you:

  • Age: Younger goldfish are a better choice due to their longer lifespan (typically 6 years). Avoid selecting fish with visible age signs like worn or frayed fins.
  • Body: Look for a goldfish with a symmetrical, medium to short body.
  • Eyes: The eyes of the goldfish should be clear, bright, and of equal size. Avoid fish with cloudy, damaged, or asymmetrical eyes.
  • Behavior: Observe the goldfish’s behavior and choose one that is active and responds well to its surroundings. A lethargic or disinterested goldfish may indicate poor health.
  • Gills: Healthy goldfish should have gills that move smoothly, without excessive laboring or gasping for air.

When looking for big-eyed goldfish, always be diligent and thorough in your quest to find healthy specimens. Keep in mind the suitable breeds for beginners and prioritize choosing the healthiest fish for your aquarium. Your dedication will pay off with happy and thriving goldfish pets.

The History and Origins of Big-Eyed Goldfish

Goldfish in China

Goldfish (Carassius auratus) were domesticated in ancient China from crucian carp, one of the most important farmed fish in global aquaculture. Their appearance in red scales on normally gray or silver crucian carp was first recorded during the Chinese Jin Dynasty (AD 265). These fish were raised in ponds and natural water bodies, eventually finding their way into the homes of people as pets.

Goldfish in Japan

In Japan, goldfish originated 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 wild goldfish began to develop vibrant colors of reds, oranges, and yellows.

Development of Telescope Goldfish

The big-eyed fancy goldfish, known as Telescope Goldfish, were first developed in China in the early 1700s through selective breeding of Tosakins and Ryukin Goldfish. Their distinctive, large eyes are due to a phenomenon called exophthalmia, which results from tissue fluid accumulation and increased pressure in the eye socket. The Chinese referred to them as “Dragon Eye Goldfish.”


Later in the 1700s, the Japanese began breeding these unique fish and gave them the name “Demekin.” Both Chinese and Japanese breeders were responsible for many Telescope Goldfish varieties that exist today. Some of these varieties include the Black Moor, Panda Moor, Butterfly Telescope, and several others, boasting different colors, fin shapes, and sizes.

Overall, the origins and development of big-eyed goldfish are rooted in the cultural history of ancient China and Japan, where they were domesticated from crucian carp and experienced variations due to selective breeding, resulting in a diverse range of unique and visually striking fish.