Comet Goldfish

Geographic Origin and Biotope: Developed and selected in the United States at the end of the 19th century from variants of the common goldfish (Carassius auratus). This morphology was designed specifically to swim freely and quickly in large outdoor ornamental basins and North American cold ponds.

Taxonomy and Morphology: Cyprinid of monumental size. Streamlined torpedo body, identical to the common but equipped with an explosion of immense fins. The caudal fin (tail) is deeply forked and almost as long as the body itself. Easily reaches 30-35 cm (12-14 inches) in total length. Pharyngeal teeth developed for bottom chewing.

Social Behavior: Frantic athlete, lively and an explorer. Unlike lazy carps or deformed Orandas, the Comet is a gentle fury: it spends the whole day in rapid mid-water sprints or scouring the bottom in a school. Although not aggressive, its enormous liveliness intimidates shy or slow fish.

Coloration and Sexual Dimorphism: Classically bright red, metallic orange, vivid yellow, or sarasa (red and white). During the mating season, triggered by spring warming, males show clear white opercular breeding tubercles, while females heavy with eggs take on an asymmetrical and swollen abdominal profile.

Aquarium Setup: Colossal fish requiring, as an absolute minimum, rectangular aquariums 150-200 cm long (over 300 liters / 80 gallons for a few specimens), although their habitat of choice remains the outdoor pond. Minimal decor to leave immense swimming lanes clear: smooth rocks, non-sharp roots, and very fine sand substrate to protect their delicate veil tails.

Diet and Feeding: Insatiable herbivore with omnivorous tendencies. Swallows whatever it finds, including tender aquatic plants. Requires high-quality sinking vegetable pellets and weekly rations of blanched fresh vegetables (primarily zucchini and peas) to keep the very long intestine clear and promote gastric regularity.

Water Quality: Formidable cold-water fish: tolerates from 10.0 to 24.0 °C. Water must be hard (GH 8.0-20.0) and slightly alkaline (pH 7.0-8.0). Mechanical and biological filtration must be industrial: the Comet produces a massive fecal load, and ammonia quickly corrodes and rots its long majestic caudal fins in closed environments.

Compatibility and Tankmates: Strict. Pair exclusively with other fast goldfish (Common Goldfish, Shubunkin, Koi Carp). Absolute ban on pairing with "Fancy" goldfish (Oranda, Moor) because the Comet is too fast and would steal all their food, condemning them to starvation. Totally incompatible with all tropical fish.

Aquarium Reproduction: Very common in outdoor ponds. Between spring and summer, males engage in frantic chases towards females, pinning them against walls or dense marsh plants to induce spawning. They release thousands of transparent, non-sticky eggs. They eat their own offspring with incredible voracity given the chance.

Risks and Diseases: In tanks that are too small, it suffers from "induced stunting", where bone growth stops but internal organs continue to grow, causing an atrocious early death. The massive veil tails are easily prone to tearing (on sharp wood) and bacterial necrosis if nitrates and ammonia are not kept near zero.