Emergency Care for an Injured Koi: Suction Trauma and Recovery Steps

Assessing the Situation

A 4-inch koi sucked through a bottom drain and trapped in a filter basket for hours has likely suffered physical trauma (scale loss, fin damage, bruising) and severe stress. The fact that it's now swimming actively is a good sign, but the refusal to eat and visible wounds require careful management.

Immediate Care Checklist

• Quarantine: Keep the koi in the 14-gallon floating bowl or a separate hospital tank. This allows close monitoring and prevents bullying.
• Water quality: Test ammonia, nitrite, and pH daily. Perform small (10–20%) water changes daily to keep ammonia low. Use a dechlorinator.
• Temperature stability: Avoid sudden temperature shifts. If moving to a heated indoor tank (9°F warmer), acclimate slowly over several hours by floating the bowl in the tank and gradually mixing water.
• Salt therapy: Maintain 0.3% pond salt (3 grams per liter) to reduce osmotic stress and support slime coat healing. Do not combine salt with certain medications—check labels.
• Wound care: Continue topical treatments (debri de ointment, bio-bandage) as directed. Avoid over-handling.
• Medication: MelaFix (tea tree oil) can help prevent secondary bacterial infections. Use with strong aeration, as it can lower oxygen.

Feeding and Companionship

Not eating for a few days is normal after trauma. Offer high-quality, soft foods (soaked pellets, bloodworms) once daily; remove uneaten food after 10 minutes. A calm companion koi can reduce stress, but monitor for any signs of aggression or nipping at wounds.

When to Consult a Vet

If the koi develops fungal patches (cottony growth), ulcerations that worsen, or remains anorexic beyond 5–7 days, seek a fish veterinarian. Injectable antibiotics may be needed for deep infections.

With clean water, low stress, and time, many koi recover remarkably well from suction injuries. Patience is key.