Fancy goldfish, scientifically known as Carassius auratus, are a charming variety of goldfish bred for their distinctive ornamental qualities. These fish differ from their common goldfish cousins with their vibrant colors, elaborate patterns, and unique body shapes, such as the notable egg-shaped body and double tail fin. Popular varieties include the Fantail, Veiltail, Oranda, and Ryukin, each with specific characteristics and care needs. Fancy goldfish can grow quite large, some reaching up to 8 inches, requiring spacious tanks with clean, well-oxygenated water. They are omnivores needing a balanced diet for health and color vibrancy. As tranquil, slow swimmers, they are perfect for cold-water aquariums, adding elegance and calmness to any home. For fancy goldfish, proper water parameters are vital for their health. Ideal conditions for a fancy goldfish tank are: Temperature: 65°F to 72°F (18°C to 22°C), pH: 7.0, General Hardness (GH): 50-120 ppm, Carbonate Hardness (KH): 70-140 ppm, Ammonia: 0 ppm, Nitrite: 0 ppm, Nitrate: Less than 40 ppm. It's crucial to maintain these parameters consistently, as fancy goldfish are more sensitive than common goldfish. Regular testing and adjustments ensure a healthy habitat for your fish.