Koi Care: A Beginner’s Guide

Understanding Koi Basics

Koi (Cyprinus rubrofuscus) are ornamental carp prized for their vivid colors, graceful movements, and long lifespans—often 25–35 years with proper care. They can grow up to 3 feet long, so they require a spacious pond with excellent water quality.

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Ideal Pond Environment

Pond Size:

• Minimum: 1,000 gallons for a small group
• Depth: At least 3–4 feet (protection from predators and temperature swings)
• Provide both open swimming areas and sheltered zones

Filtration:

• Mechanical filtration removes debris
• Biological filtration processes ammonia into less harmful compounds
• UV clarifiers help control algae blooms

Water Parameters for Healthy Koi:

• Ammonia: 0 ppm
• Nitrite: 0 ppm
• Nitrate: < 40 ppm
• pH: 7.0–8.5 (stable, minimal daily swings)
• Temperature: 59–77°F (15–25°C) preferred
• Dissolved Oxygen: 6+ mg/L

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Feeding Guidelines

Seasonal Feeding:

• Spring (59–68°F / 15–20°C): Start with wheat germ–based food for easy digestion
• Summer (68–77°F / 20–25°C): Feed high-protein growth pellets twice daily
• Fall (59–68°F / 15–20°C): Switch back to wheat germ food, reduce frequency
• Winter (< 50°F / 10°C): Stop or drastically reduce feeding—koi metabolism slows

General Tips:

• Feed only what koi consume in 5 minutes
• Overfeeding leads to poor water quality
• Offer occasional treats (shrimp, watermelon, peas)

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Stress Reduction and Health

Preventing Stress:

• Avoid sudden water temperature or chemistry changes
• Keep stocking density low (ideally < 1" fish length per 10 gallons)
• Provide hiding spots (plants, caves)
• Use aeration to maintain oxygen levels during summer heat

Quarantine New Fish:

• 2–4 week quarantine in a separate tank or pond
• Observe for parasites, fungus, or abnormal behavior

Common Koi Health Issues:

• Ich (white spot disease): Treat promptly with temperature adjustments and medication
• Ulcers: Usually bacterial, linked to poor water quality or injury
• Parasites: Scraping and microscopy needed for diagnosis

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Seasonal Koi Care in Texas

Spring (March–May):

• Resume feeding when water stays above 50°F
• Test water weekly
• Remove debris from winter
• Watch for spawning behavior

Summer (June–August):

• Provide shade to prevent overheating
• Ensure strong aeration
• Check for algae blooms
• Feed more often, but in small amounts

Fall (September–November):

• Reduce feeding as water cools
• Remove excess organic debris
• Prepare for overwintering

Winter (December–February):

• Stop feeding below 50°F
• Keep pond surface from fully freezing
• Minimize disturbances to dormant koi

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Pond Design Tips for Koi

• Use sloped sides to discourage predators
• Incorporate deep areas for summer cooling and winter warmth
• Include waterfalls or air pumps for oxygenation
• Avoid sharp edges or rough surfaces that can injure fish

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Quick Problem-Solving Guide

• Cloudy Water: Check filtration, reduce feeding, partial water change
• Koi Gasping at Surface: Increase aeration, check ammonia levels
• Loss of Color: Improve diet with spirulina and fresh greens, ensure good water quality

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Where to Get Koi in Texas

• Specialty Koi Dealers: Offer healthy, quarantined stock and expert advice
• Pond & Water Garden Centers: Often carry hardy varieties suited to local climate
• Koi Shows & Clubs: Great for rare color patterns and networking with experienced keepers

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With proper water quality management, a balanced diet, and careful seasonal adjustments, your koi will reward you with vibrant colors, active swimming, and decades of beauty in your pond.