🧬 Origins and Classification
Scientific Name: Cyprinus rubrofuscus (domestic Koi)
Family: Cyprinidae
The Koi (XXLarge) is a fully grown, show-sized koi carp prized for its size, color, and elegant movement. Originating from Japan, koi have been selectively bred for centuries for their stunning patterns and symbolic meaning. An XXLarge Koi often becomes the centerpiece of a pond because of its impressive length and calm, majestic behavior.
🎨 Appearance
The Koi (XXLarge) displays bold coloration and refined markings that stand out beautifully in outdoor ponds.
Color & Features:
- Bright patterns: red, orange, white, black, yellow, and metallic varieties
- Thick, powerful body shape
- Smooth, flowing fins
- Highly visible scales that shimmer in sunlight
Size:
- XXLarge: 20–28 inches or more (depending on variety and age)
- Lifespan: 20–30 years, with some living even longer
🏡 Pond Requirements
Pond Size:
Because of their size, Koi (XXLarge) require a large pond — minimum 1,000 gallons, but more is always better.
Water Parameters
- Temperature: 59–77°F (15–25°C)
- pH: 7.0–8.5
- Hardness: Moderate to hard
- Strong oxygenation is essential
Environment Setup
To keep an XXLarge Koi healthy, provide:
- Deep pond areas (3–4 feet minimum)
- Strong filtration (koi produce heavy waste)
- Aquatic plants and shaded zones
- Smooth rocks and safe décor
- Good water circulation
Large koi thrive in clean, well-maintained ponds with room to swim freely.
🍽️ Diet
Type: Omnivorous
Food Options:
- High-quality koi pellets
- Floating pond sticks
- Frozen treats: shrimp, bloodworms
- Fresh vegetables: peas, lettuce, watermelon (in small portions)
Feed 1–2 times per day depending on temperature; koi eat less in cooler months.
🤝 Behavior and Compatibility
The Koi (XXLarge) is peaceful, social, and intelligent. They coexist well with other koi and large pond fish.
Ideal Pond Mates:
- Goldfish varieties
- Shubunkins
- Orfe
- Plecostomus (in warm climates)
Avoid:
- Small fish that could be mistaken for food
- Sharp décor or cramped ponds
Koi often learn to recognize their keepers and will come to the surface for feeding.
💡 Care Notes
Maintaining water quality is essential for XXLarge koi. Perform regular water changes, monitor ammonia and nitrate levels, and ensure the pond filter is powerful enough to handle their size. Because large koi grow slowly after reaching maturity, a stable environment helps them maintain bright colors and a strong immune system.
The Koi (XXLarge) is ideal for large ponds and for keepers who want a visually stunning, long-lived fish that becomes the highlight of their water garden.



