Egg Fish Goldfish (Care Guide)

three aquatic animals described

The Egg Fish Goldfish is a unique type of ornamental fish known for its round body and lack of a dorsal fin, which gives it a graceful swim. It comes from Asia and is important for breeding many other goldfish types.

Those who keep Egg Fish Goldfish must pay attention to many care details, including tank setup and diet. The beauty of the fish is clear, but they require a lot of effort to take care of properly. Owners need to understand both how the fish looks and the work needed to keep it healthy.

Breed Introduction

The egg-fish goldfish has been selectively bred for centuries and has a unique look with various colors and scale designs. They can live over ten years with proper care, but their lifespan depends on care quality.

They are notable for their lack of a dorsal fin and are of interest to both enthusiasts and the general public.


The egg-fish goldfish, especially the phoenix type, is recognized by its egg-shaped body without a dorsal fin and headgrowth. This breed, which originated in China, is known for its smooth and rounded shape. The phoenix egg-fish comes in various colors, adding to its charm.

In Japan, it’s called Maruko and holds cultural significance in both China and Japan. Caring for these goldfish can be somewhat challenging, as they require careful attention to stay healthy and exhibit proper social behavior.


The egg-fish goldfish, including the phoenix variety, is known for its unique look and can live longer than ten years with proper care. Originating from China and Japan, this goldfish breed is now a social pet that can interact with its owners.

High water quality is crucial for its health due to its sensitivity. Careful management can lengthen its lifespan. The egg-fish goldfish is peaceful and does well in a controlled tank, offering both historic significance and the possibility of long-term companionship.


Egg-fish goldfish, also known as Maruko in Japan, typically grow to a length of 6 inches. They are a medium-sized goldfish breed recognized by their egg-shaped body, especially in the phoenix variety which lacks a dorsal fin. This shape sets them apart from other goldfish breeds.

They have been significant in Chinese and Japanese culture for over 800 years.

Egg-fish goldfish require careful care due to their delicate nature. They are social and suitable for community aquariums with appropriate tank mates.

Aquarium Configuration

For an egg fish goldfish aquarium, choose a tank size that meets the space needs and swimming habits of the breed.

Add suitable equipment and decorations to mimic their natural environment and promote their health.

The design should prioritize the goldfish’s specific requirements while maintaining visual appeal.

Tank Size

A 20-gallon tank is the minimum size for one adult egg fish goldfish. Each additional goldfish requires an extra 10 gallons of space.

A 40-gallon tank or larger is recommended to ensure enough space for swimming and to avoid growth issues. A wide, shallow tank design is best for the goldfish’s egg-shaped body and helps with oxygen exchange. Avoid deep tanks that can hinder the goldfish’s swimming.

Strong filtration and regular water changes are necessary to keep the water clean and healthy for the fish.

Tank Equipment And Decorations

Setting up an aquarium for egg-fish goldfish requires selecting a filter, heater, and lighting that support their specific needs. Ensuring high water quality is essential for these decorative fish. When arranging the aquarium, consider the following for the well-being of egg-fish goldfish:

  • A strong filtration system to maintain clean, oxygen-rich water.
  • An adjustable heater to keep water temperature consistent.
  • LED lighting to mimic natural light cycles without increasing water temperature.
  • Smooth rocks, driftwood, and live or artificial plants for shelter and stimulation.

Place items carefully to avoid injuries and provide enough space for the fish.

Health and Wellness

The health of egg fish goldfish depends on their diet, water quality, and tank upkeep. A balanced diet and proper water conditions prevent diseases.

Regular cleaning and illness checks are crucial for their well-being and lifespan.


Egg-fish goldfish require a diet that includes high-quality flakes or pellets as the main component. This diet should also include various vegetables and occasional protein treats to maintain their health and round body shape. The specific needs of fancy goldfish must be considered when selecting food.

  • Use goldfish-specific flakes or pellets that cater to the nutritional requirements of fancy goldfish.
  • Incorporate vegetables such as peas without shells and zucchini slices for fiber.
  • Establish a feeding routine to avoid overfeeding and potential health problems.
  • Provide protein sources like bloodworms or brine shrimp occasionally for dietary variety.

It’s important to monitor the food intake of egg-fish goldfish to ensure their well-being.

Water Parameters

A proper diet is essential for egg-fish goldfish health, but so is maintaining the right water parameters. Water quality is crucial for their survival. Aquarists should test and adjust water regularly to ensure a stable environment for the fish.

ParameterIdeal RangeNotes
Temperature65-72°F (18-22°C)Keep temperatures constant.
pH Level7.2-7.6Maintain stability to prevent stress.
Ammonia0 ppmHarmful at any concentration.
Nitrites0 ppmShould not be present.
Nitrates< 40 ppmLevels above 40 ppm are a sign of poor water quality.

Monitoring and maintaining these parameters is crucial for the health of egg-fish goldfish.

Tank Maintenance

Tank maintenance is essential for the health of egg-fish goldfish. Regular water changes and filter checks are necessary to maintain water quality. Monitor pH, ammonia, nitrite, and nitrate levels.

Clean the tank substrate with a vacuum to remove food and waste, preventing water pollution. Clean tank decorations and equipment, such as heaters and air pumps.

Maintain stable water temperatures and ensure good water circulation to support the health of the goldfish.

Common Diseases

Egg-fish goldfish can develop various diseases despite careful tank maintenance. Maintaining high water quality is crucial, but health issues may still arise, requiring vigilant care from aquarists. It is important to recognize symptoms and know how to treat these diseases.

  • Ichthyophthirius Multifiliis (Ich): This disease causes white, grainy spots on the skin, fins, and gills.
  • Fin Rot: The fins may look frayed or change color, commonly due to subpar water conditions or a bacterial infection.
  • Swim Bladder Disease: Affected fish may swim erratically or struggle with buoyancy, which can be related to excessive feeding.
  • Fungal Infections: White, fluffy growths on the skin, mouth, or gills suggest a weakened immune system or an injury.

Temperament and Social Traits

Egg-fish goldfish are social and interact with their human caretakers and other fish. They are popular for group tanks due to their friendly behavior. These fish recognize their owners and respond eagerly, showing intelligence and adaptability.

Egg-fish goldfish prefer calm environments and get along with fish of similar size and shape. They can learn tricks, despite their body shape and slower movement, which shows their willingness to engage with humans.

For the well-being of egg-fish goldfish, it is important to provide a suitable habitat with compatible species. They are active members of a tank community, providing interaction and companionship. Their health and happiness depend on proper care from the fish keeper.

With appropriate care, egg-fish goldfish are rewarding pets that contribute positively to their aquatic community.

Compatible Tank Companions

Choosing tank mates for egg-fish goldfish requires selecting non-aggressive species with similar habitat needs to maintain a peaceful aquarium. Suitable companions include other fancy goldfish varieties that need similar care. These should coexist without conflict and enhance the tank’s overall appearance.

Suitable tank mates for egg-fish goldfish include:

  • Fantail Goldfish: Their flowing fins and calm behavior match well with egg-fish goldfish.
  • Ranchu Goldfish: These fish are non-aggressive and do not have a dorsal fin, making them good companions.
  • Lionhead Goldfish: They have a distinctive ‘wen’ and are calm, adding variety to the tank.
  • Pompom Goldfish: Their unique nasal outgrowths contribute to the visual interest while being peaceful.

When adding new fish, monitor for aggression or stress and separate if necessary to protect all fish. Selecting compatible tank mates is key to a healthy and engaging aquarium community.

Reproduction Techniques

Reproduction techniques for egg-fish goldfish, particularly the Phoenix egg goldfish variety which lacks a dorsal fin, are critical for successful breeding. The breeding environment should mimic their natural habitat with correct water temperature and a suitable spawning substrate.

During the breeding phase, male Phoenix egg goldfish chase and nudge females, triggering egg release. Breeders must oversee this to avoid complications.

Post-spawning, eggs are moved to a nursery tank to prevent predation by the adults, with a focus on clean water and consistent temperature for proper egg development and fry hatching.

Pairing Phoenix egg goldfish with similarly paced fancy goldfish during breeding is recommended to prevent stress and ensure a fair competition for resources.

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