Comet Goldfish

The Comet Goldfish is a selectively bred form of goldfish, distinguished by its elongated, streamlined body and a long, deeply forked single caudal fin, resembling a fork. The fins can be significantly longer than the body. The coloration is diverse: from classic red and orange to white, lemon-yellow, or combinations of these colors with spots. Adults reach 15–20 cm in length; in pond conditions, they can grow up to 30 cm. Sexual differences become noticeable during the spawning period: males develop small white tubercles on their gill covers and serrations on their pectoral fins.

The Comet Goldfish does not exist as a natural species in the wild; it is an artificially bred variety. Its ancestor, the silver crucian carp (Carassius auratus), inhabits slow-moving or stagnant waters of East Asia (rivers, lakes, ponds), preferring areas with abundant aquatic vegetation and soft substrate. Comet Goldfish are adapted to life in temperate climates and can tolerate significant fluctuations in water temperature.

Comet Goldfish are very active, swift, and mobile fish, requiring ample swimming space. They are peaceful, but due to their high speed and activity, they may compete for food with slower species, so it is best to keep them in a species-specific tank or with other active coldwater fish. They are social and prefer to stay in groups.

For a single specimen an aquarium of at least 150 litres is recommended, plus about 40 litres for each additional fish — the comet grows to 30 cm and is very active. Powerful filtration and regular aeration are necessary, as the fish produce a lot of organic waste. The optimal water temperature is 18–23 °C, hardness 5–19 dGH, pH 6–8. For substrate, large, rounded pebbles without sharp edges are preferred to avoid damaging the fins. The aquarium must be covered with a lid, as the fish can jump out.

Omnivorous fish with a pronounced herbivorous tendency. The diet should consist of specialized goldfish food (pellets are preferred), supplemented with plant-based foods (blanched lettuce leaves, spinach, zucchini, cucumbers) and protein additives (brine shrimp, bloodworms). Feed 1–2 times a day in small portions that are consumed within a few minutes to avoid water pollution.

Breeding is relatively straightforward. For spawning, a separate aquarium with fine-leaved plants or spawning mops is recommended. The stimulus is a gradual increase in water temperature to 20–23 °C and an extended photoperiod. After spawning, the parents should be removed, as they tend to eat the eggs. Fry are fed with infusoria, Artemia nauplii, or specialized starter foods.

The most common problems are associated with poor water quality and the accumulation of nitrogenous compounds. Bacterial infections, fin rot, fungal infections, and swim bladder disorders (bloating, loss of balance) are common. Prevention includes regular water changes, parameter control, and avoiding overfeeding.

When purchasing, choose active, well-fed individuals with clean scales, free of damage, ulcers, or white spots. Eyes should be clear, without cloudiness. Fins should be spread, with even edges, and no signs of deterioration. Avoid fish that lie sluggishly on the bottom or have an unnaturally bloated abdomen.