Goldfish - Carassius auratus auratus

Scientific name: Carassius auratus auratus

Common name: Goldfish

Family: Cyprinidae

Usual size in fish tanks: 16 - 20 cm (6.3 - 7.87 inch)

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Recommended pH range for the species: 6 - 8

Recommended water hardness (dGH): 4 - 18°N (71.43 - 321.43ppm)

0°C 32°F30°C 86°F

Recommended temperature: 15 - 24 °C (59 - 75.2°F)

The way how these fish reproduce: Spawning

Where the species comes from: South Asia

Temperament to its own species: peaceful

Temperament toward other fish species: peaceful

Usual place in the tank: Bottom levels

Guidelines for Caring for Goldfish

Goldfish (Carassius auratus auratus) are large, active fish that require ample space to thrive. Each Goldfish needs at least 45 liters (12 gallons) of water, so a group of four requires an aquarium of 181 liters (48 gallons), and six would need a tank of 272 liters (72 gallons). A spacious environment not only supports their growth but also helps maintain stable water quality.

Never introduce Goldfish into an uncycled tank. While they are considered hardy, unstable water parameters can cause stress, weakening their immune system and leading to infections or disease. Weekly water changes of 10-15% are crucial to maintain a clean, healthy environment. Goldfish are a coldwater species and should not be kept in tropical setups; the water temperature should always remain below 24°C (75.2°F).

It’s advisable to avoid keeping fancy Goldfish with common varieties. Fancy Goldfish are less hardy and may become targets of bullying by their more robust counterparts, leading to stress and potential health issues.

Food and Feeding

Goldfish are omnivores that thrive on a diet low in protein and high in carbohydrates. To meet their nutritional needs, use specialized Goldfish flakes or pellets formulated for their dietary requirements. Feed them small portions twice daily, limiting the amount to what they can consume within two minutes. This prevents overfeeding, which can lead to digestive problems.

Supplement their diet with fresh foods such as shelled peas, blanched leafy vegetables, and occasional protein sources like bloodworms. These additions help diversify their diet and promote better health and coloration. Although Goldfish may always appear hungry, resist the urge to overfeed, as this can lead to obesity and water quality issues.

Origin

Goldfish originate from Asia and are closely related to the native brown carp. Through centuries of selective breeding, various gold and ornamental strains have been developed, leading to the wide range of Goldfish varieties seen today.

Sexing

Sexing Goldfish can be challenging outside the breeding season. During spawning, males often develop white spots, known as breeding tubercles, on their gill plates. Females may appear rounder when carrying eggs, but these differences can be subtle and are not always reliable indicators of sex.

Breeding

Goldfish breeding is generally easier in ponds but is also achievable in large aquariums. During the breeding season, the female lays sticky eggs on plants or other surfaces. These eggs typically hatch within 48-72 hours. The fry are very small at birth and initially retain a brown coloration, much like their wild ancestors. It may take up to 12 months for them to develop their adult colors.

For successful breeding, maintain optimal water conditions and provide ample hiding places for the fry. A separate breeding tank can be used to protect the eggs and fry from being eaten by adult fish. Feed the fry with specialized fry food or newly hatched brine shrimp to support their rapid growth.

Lifespan

Goldfish have a relatively long lifespan, ranging from 10-15 years under normal circumstances. However, with excellent care and an optimal environment, they can live up to 45 years. Regular maintenance, a balanced diet, and proper tank conditions are key to helping Goldfish reach their full lifespan.

Tank Setup and Environment

Goldfish require a well-maintained tank with plenty of swimming space. A minimum of 45 liters (12 gallons) per fish is recommended to accommodate their size and activity level. Goldfish produce a significant amount of waste, so a powerful filtration system is necessary to keep the water clean and reduce the risk of ammonia build-up.

Goldfish prefer a temperature range of 15-24°C (59-75.2°F) and a pH between 6 and 8. They do not require a heated tank, making them ideal for coldwater aquariums. Substrate and decorations should be smooth to prevent injury, as Goldfish are known to root around the tank bottom. Avoid sharp or rough objects that could damage their delicate fins.

While Goldfish can be kept with other coldwater species like some Danios and Minnows, ensure that tank mates are large enough to avoid being mistaken for food. Additionally, provide plants or ornaments that offer hiding places and enrich their environment.

Short Description

Goldfish are one of the most popular freshwater fish due to their variety, hardiness, and captivating behavior. Despite their reputation as easy-to-keep pets, they require specific care to thrive. Proper tank size, water quality, and diet are crucial for their well-being. They are peaceful and can be kept with other coldwater fish species that share similar water requirements. However, their large size and active nature necessitate a spacious tank with robust filtration. Goldfish can be a long-term commitment, offering many years of companionship when cared for correctly.