Ryukin Goldfish - Carassius auratus : Complete Fish Profile & Care Guide
Table of contents
Introduction
The Ryukin Goldfish (Carassius auratus), a distinctive and resilient variant of the Goldfish, is a selectively bred form characterised by a high back and double tail. These fancy Goldfish are long-standing favourites in aquariums and often serve as an introduction to fishkeeping for many enthusiasts.
Ryukins are sociable and best kept in groups, either with other Ryukins or compatible Goldfish varieties such as Pearlscale, Lionhead, and Ranchu. Adequate space and proper maintenance allow for the harmonious cohabitation of different species. It is advisable to avoid housing them with faster-swimming, single-tailed common Goldfish, which may dominate during feeding times. Compatible species like Weather Loaches, Chinese Blue Bitterlings, and Northern Redbelly Dace can also be added. These Goldfish adapt well to both freshwater and tropical aquariums, provided there are no aggressive or territorial fish present.
A spacious aquarium with ample surface area for oxygen exchange is crucial. Prioritising tank length and width over height is key, especially as fancy Goldfish grow rapidly. Starting with the largest possible aquarium prevents stunting and ensures a stable environment. Larger water volumes are beneficial for maintaining consistent water chemistry and temperature.
Efficient filtration and regular partial water changes are vital to minimise nitrate levels. Well-oxygenated water can be achieved through spray-bar returns from filters, air pumps, and small powerheads directed towards the water's surface. Oxygenating aquatic plants not only enhance oxygenation but also provide natural food sources for the fish. Though these plants may need frequent replacement due to being uprooted or consumed, most Goldfish keepers find this acceptable. The substrate can be rounded gravel or sand, and décor should include smooth rocks and ornaments without sharp edges.
Ryukin Goldfish are recognised by their pointed head and prominent hump behind the head. They can have long or short fins with triple or quadruple tails. The dorsal fin is notably high, and the caudal fin can be twice the body length, sometimes with three or four lobes. Ryukins display a variety of colours, including deep red, red-and-white, white, silver, blue, black, orange, lavender grey, iron, and calico.
Ryukin Goldfish Photos
Sexual Dimorphism
Distinguishing between male and female Ryukin Goldfish is a relatively straightforward process. Mature females typically exhibit a more rounded body shape, particularly noticeable when viewed from above. In contrast, mature males display breeding tubercles on their gill plates and pectoral fins. As a general rule, males tend to be smaller and more slender compared to females. Ryukin Goldfish reach sexual maturity and become capable of reproduction at approximately five months of age.
Quick Facts
| Scientific Name | Carassius auratus |
|---|---|
| Other Names | Japanese Ribbontail Goldfish, Fringetail Goldfish, Fantail Goldfish, Veiltail Goldfish |
| Kingdom | Animalia |
| Classification | Actinopterygii |
| Order | Cypriniformes |
| Family | Cyprinidae |
| Genus | Carassius |
| Origins | |
| Max Size | 20 cm |
| Temperament | Peaceful |
| Aquarium Level | All Levels |
| Difficulty | Beginner - Intermediate |
| Shoaling | No |
| Best kept as | Trios |
| Diet & Feeding | Omnivore |
| Reproduction | Egg Depositor |
| Average Lifespan | Up to 10 Years |
Water Parameters
| Water Type | Freshwater |
|---|---|
| pH | 6.0 - 8.0 |
| GH | 5 - 20 |
| ℉ | 65 - 72 |
|---|---|
| ℃ | 18 - 22 |
Natural Habitat
The Ryukin Goldfish has its origins in China. The exact timeline of its breeding is unclear, but it is widely believed to be a mutation derived from the Wakin Goldfish. The name "Ryukin" is attributed to its supposed introduction to Japan via the Ryukyu Islands, presently known as Okinawa Prefecture, situated between Taiwan and Japan. This historical pathway highlights the species' journey and development across East Asian regions.
Breeding
In a well-maintained aquarium environment, Ryukin Goldfish are capable of successful spawning. Initiating this process often involves a significant water change with slightly cooler water, which can stimulate spawning in ready pairs. As the water temperature gradually returns to its normal range, the male Ryukin engages in a generally non-aggressive pursuit of the female throughout the tank.
This pre-spawning courtship can extend over a day or more, during which the fish's colours may become more vibrant. The male guides the female towards fine-leaved plants or spawning mops, where she releases eggs that the male simultaneously fertilizes.
The spawning process can span several hours, with potentially thousands of adhesive eggs deposited among the plants or on the spawning mop. Post-spawning, the adult fish often exhibit an increased appetite and may consume the eggs, making it advisable to relocate them to a separate aquarium. The eggs typically hatch within 4-5 days, subject to water temperature. It is noteworthy that young fancy Goldfish usually appear brown initially, with their full colouration developing over the course of a year.
Diet & Feeding
Proper care for Ryukin Goldfish involves providing a balanced diet that includes high-quality flake food daily. Supplement this with occasional treats such as brine shrimp, bloodworms, Daphnia, or tubifex worms. It is advisable to opt for freeze-dried versions of these foods rather than live ones to minimize the risk of parasites and bacterial infections that live foods might carry. Ryukin Goldfish typically feed four to five times daily, not including snacks. This feeding frequency helps maintain their health and vitality.
