Fantail Goldfish

The Fantail Goldfish is a selectively bred variety of goldfish, characterized by a shortened, rounded, or egg-shaped body and a large caudal fin. Unlike many other decorative breeds, the most typical representatives have a single caudal fin, although in common aquarium practice, various forms with a simplified tail structure are often grouped under this name. Coloration varies from classic red-orange to white, spotted, or pearlescent. Adult individuals reach a size of about 15 cm.

In the wild, goldfish inhabit freshwater bodies of East Asia, including China and Japan. They populate rivers, lakes, ponds, and canals with still or slow-moving water, often choosing areas with dense vegetation. In natural conditions, the species exhibits high ecological plasticity, tolerating significant water temperature fluctuations from 0 to 41°C and a wide range of hardness.

These fish have a calm, peaceful disposition, but can be slow swimmers. Due to the peculiarities of their body and fin structure, they are slower than more active species, so it is not recommended to keep them with aggressive or very nimble tank mates. Fantails tend to search for food in the substrate, often digging through it, which requires the use of a soft substrate.

For keeping a single specimen, an aquarium of at least 40 liters is required; however, for a comfortable existence of a group of fish, more spacious tanks are preferable. Important conditions include powerful filtration and regular water changes, as these fish produce a lot of organic waste. The optimal water temperature is 18–22°C. Fine sand is best used as substrate, as large gravel can injure the fish or get stuck in its mouth. The decor should be free of sharp objects that could damage the fins.

The species is omnivorous and has a pronounced appetite. The diet should include specialized dry foods for goldfish in the form of flakes or pellets, supplemented with plant-based foods and frozen foods such as Artemia or bloodworms. Feeding is recommended 1–2 times a day in small portions to avoid overeating and excessive water pollution from food remnants.

Breeding is achieved through spawning, which is usually stimulated by an increase in water temperature. Sexual dimorphism is weakly expressed; males and females can mainly be distinguished during the period of preparation for reproduction. Eggs are laid on fine-leaved plants or special substrates. Fry require sorting and high-quality feeding, and offspring often include individuals with deviations from the breed standard.

These fish are sensitive to water quality and the accumulation of organic compounds, which can provoke bacterial infections and fin diseases. Common problems include obesity due to improper feeding and injuries sustained from sharp objects in the aquarium. Prevention involves maintaining water cleanliness, adhering to the feeding regimen, and ensuring the absence of dangerous decor in the aquarium.

When purchasing, choose active fish with clean fins showing no signs of damage, growths, or ulcers. The body should be symmetrical, without visible deformities, and the eyes clear. It is recommended to observe the individual's behavior in the store: a healthy fish shows interest in its surroundings and does not constantly stay at the surface or bottom in a depressed state.