Koi Pond Spring Cleaning 2026 | Post-Winter Revival Guide

Your koi just survived one of nature’s most brutal tests: a Chicago winter.

For 12-16 weeks, they sat motionless at the bottom of your pond in near-freezing water. They didn’t eat. They barely moved. Their metabolism slowed to almost nothing. Their immune systems shut down.

And now it’s spring.

The water is warming. Your koi are starting to wake up. And the decisions you make in the next 4-6 weeks will determine whether they thrive all season or whether you’re dealing with disease outbreaks, parasite infestations, and mortality by June.

Here’s what most koi owners don’t realize: Spring is the most dangerous time of year for koi. More koi die in April and May than any other month. Not because of the winter but because of what happens when they wake up from winter.

This guide will show you exactly how to bring your koi through spring safely. You’ll learn:

• When to start spring cleaning (too early kills fish)
• Complete koi health inspection protocol
• The 50°F feeding rule (break this, lose fish)
• How to restart your biological filter for koi waste
• Spring disease prevention strategies
• What to watch for in the critical first 30 days

Full transparency: We’ve been maintaining koi ponds in Chicago since 2005. We’ve seen what works and what doesn’t. We’ve also seen what kills expensive koi and most of it happens in spring because owners rush the process.

Let’s make sure that doesn’t happen to you.

Why Koi Ponds Need Different Spring Care Than Goldfish Ponds

If you’re coming from general pond care articles, stop. Koi are different.

The Critical Differences

Koi vs. Goldfish:

Factor	Goldfish	Koi
Value	$3-25 each	$50-$5,000+ each
Stress sensitivity	Moderate	High
Disease susceptibility	Low	High
Immune system	Hardy	Compromised post-winter
Growth rate	Slow	Fast (need quality food)
Lifespan	10-20 years	25-50+ years
Owner investment	Casual	Serious

Why this matters for spring cleaning:

With goldfish:

• Quick cleaning is usually fine
• Basic water quality acceptable
• Can handle more stress
• Disease risk is lower
• Feeding restart is simpler

With koi:

• Slow, careful approach essential
• Premium water quality required
• Minimize every stress factor
• Disease prevention critical
• Feeding restart is science

Bottom line: If you have $2,000-$10,000 worth of koi in your pond, you can’t treat spring cleaning like a casual weekend project. These fish are an investment and spring is when that investment is most vulnerable.

The Chicago Koi Winter Reality Check

Let’s talk about what your koi just went through.

Chicago Winter Stats (2025-2026)

What your koi endured:

• 94 consecutive days below freezing (Dec-Feb)
• 23 days below 0°F
• Pond water: 34-39°F for 14+ weeks
• Ice thickness: 18-24 inches
• Zero sunlight penetration through ice/snow
• No feeding for 4-5 months
• Minimal dissolved oxygen

What happens to koi in these conditions:

Metabolism:

• Normal: 100% (summer)
• Winter: 3-5% (torpor state)
• They’re barely alive

Immune system:

• Normal: Active and responsive
• Winter: Severely suppressed
• Unable to fight disease or parasites

Body condition:

• Weight loss: 10-20% of body mass
• Muscle wasting (protein breakdown)
• Fat reserve depletion
• Organ stress (liver, kidney)

Stress hormones:

• Elevated cortisol throughout winter
• Weakened cellular repair
• Reduced healing capacity

The critical point: When spring arrives, your koi aren’t just “waking up feeling refreshed.” They’re emerging from months of starvation and stress with compromised immune systems and they’re about to enter the most disease-prone time of year.

Spring Timing: The 50°F Rule (Break This, Lose Fish)

The #1 mistake Chicago koi owners make: rushing spring.

The 50°F Rule Explained

DO NOT begin feeding, cleaning, or handling koi until water temperature is CONSISTENTLY above 50°F.

Why 50°F is the magic number:

Below 50°F:

• Koi digestive system barely functional
• Food sits in stomach and rots (causes death)
• Immune system still suppressed
• Cannot handle stress of cleaning
• Disease pathogens dormant (good)

Above 50°F:

• Digestive system begins reactivating
• Can process food slowly
• Immune system starting to wake up
• Can tolerate moderate stress
• Disease pathogens becoming active (risk begins)

Above 60°F:

• Fully active metabolism
• Normal feeding possible
• Immune system functional
• Disease risk highest (parasites/bacteria thrive)

What “Consistently Above 50°F” Means

NOT just one warm day. You need:

• 3-5 consecutive days with water temp 50°F+
• Daytime highs 55-60°F air temperature
• Nighttime lows staying above 40°F
• No cold front forecast for next 7 days

In Chicago, this typically occurs:

• Earliest: April 5-10 (warm spring)
• Average: April 15-20 (normal spring)
• Latest: April 25-May 5 (cold spring)

Pro tip: Buy a pond thermometer with memory. Check water temp daily starting in late March. Track the trend. When you see 5+ days consistently above 50°F, you can proceed.

What happens if you rush it:

Client story – Wheaton, 2023:

• March 28: Single warm day, water hit 52°F
• Owner started feeding and cleaning
• March 30-April 2: Cold snap, water dropped to 44°F
• By April 5: Lost 3 koi to digestive shutdown
• Total loss: $1,400 in fish

Don’t be this person.

Pre-Cleaning Koi Health Assessment (Do This First!)

Before you touch your pond or handle fish, observe them for 3-5 days.

Visual Inspection (Through the Water)

Watch for these signs during the “wake-up” phase:

Healthy behaviors: 

✅ Gradual increase in activity over several days
✅ Slow, steady swimming near bottom
✅ Occasional surface visits
✅ Response to your presence (eventually)
✅ Breathing rate: 60-80 gill beats per minute at 50°F

Concerning behaviors:
⚠️ Gasping at surface constantly
⚠️ Erratic swimming or spinning
⚠️ Flashing (rubbing on rocks/bottom)
⚠️ Isolation (one koi alone, not schooling)
⚠️ Floating near surface (buoyancy issues)
⚠️ Clamped fins (fins held tight to body)

Critical warning signs:
🚨 Red streaks on body or fins (septicemia)
🚨 White spots (ich)
🚨 Cotton-like growth (fungus)
🚨 Ulcers or open wounds
🚨 Bloating or pineconing (scales sticking out)
🚨 Not moving at all after 50°F reached

If you see ANY critical warning signs:

• DO NOT proceed with cleaning
• DO NOT handle fish
• Call a koi vet or koi specialist immediately
• Treating disease before cleaning is essential

Contact: We can refer you to koi vets in the Chicago area. Call (630) 407-1415.

The Koi-Safe Spring Cleaning Process (Step-by-Step)

This is NOT the same as regular pond cleaning. Koi require extra care.

Preparation Phase (2-3 Days Before)

Get your koi ready for the stress:

Step 1: Water Quality Baseline

• Test ammonia (should be 0)
• Test nitrite (should be 0)
• Test pH (should be 7.0-8.0)
• Test KH (should be 80-120 ppm)
• Document results

Why this matters: If water quality is already bad, cleaning will make it worse. Fix issues first.

Step 2: Set Up Superior Fish Holding

Koi need better holding conditions than goldfish:

Container requirements:

• Minimum 100 gallons per 5-6 adult koi
• Must be deeper than wide (koi need depth)
• Dark color preferred (reduces stress)
• Cover available (jumping prevention)

Aeration requirements:

• Heavy aeration (double what you’d use for goldfish)
• Air stones at multiple points
• Backup air pump on standby

Water requirements:

• Use 100% pond water (not tap water)
• Temperature must match pond exactly
• If adding fresh water, dechlorinate heavily

Location requirements:

• Full shade (no direct sun)
• Protected from wind
• Away from loud noises
• Safe from predators (herons WILL find your holding tank)

Step 3: Prepare Koi Health Station

Set up an inspection area:

• Shallow examination bowl/tub
• Soft knotless nets (2 sizes)
• Magnifying glass or jeweler’s loupe
• Notepad for documenting observations
• Camera/phone for photos
• Gloves (if you must handle, wet gloves only)

Day of Cleaning: The Koi-Safe Protocol

Key difference from goldfish ponds: Everything slower, gentler, more careful.

Step 1: Catching Koi (The Gentle Way)

DO NOT chase koi frantically. This kills them.

Proper technique:

1. Wait 10-15 minutes after approaching pond (let them settle)
2. Use two people if possible (one blocks, one catches)
3. Use corner herding method (don’t chase in circles)
4. Net from front/side, never from above
5. Support full body weight immediately
6. Minimize air exposure (under 30 seconds)

Koi-specific handling:

• NEVER squeeze mid-body (damages organs)
• Support head and tail simultaneously
• Keep wet at all times
• ONE person handles each koi
• Work slowly speed kills

Special considerations for large koi (20+ inches):

• Use bowl/tub transfer method (don’t lift in net)
• May require 2 people
• Extra careful with breeding females (heavy with eggs)

Step 2: Individual Koi Health Inspection

This is where koi care differs most from goldfish.

Inspect EVERY koi individually as you catch them:

Body inspection checklist:
☐ Overall body condition (thin? bloated? normal?)
☐ Scale pattern (missing scales? damage?)
☐ Skin quality (slimy coating present? dry patches?)
☐ Color (faded? blotchy? normal for post-winter?)
☐ Eyes (clear? cloudy? sunken? bulging?)
☐ Gills (red/pink? white/pale? dark red?)
☐ Fins (torn? frayed? clamped? rot visible?)
☐ Vent area (prolapsed? swollen? red? normal?)

Parasite screening:
☐ Look for white spots (ich) – pinhead-sized
☐ Look for anchor worms – thread-like protrusions
☐ Look for fish lice – flat disc-like parasites
☐ Check for flukes – excess slime, flashing behavior
☐ Examine gills closely – any visible parasites?

Disease screening:
☐ Red streaks (bacterial septicemia)
☐ White cottony growth (fungus)
☐ Ulcers or open sores (bacterial infection)
☐ Pop-eye (bacterial/parasitic)
☐ Dropsy symptoms (pineconing scales)

Document everything:

• Photograph each koi
• Note any abnormalities
• Record in log: Koi ID, observations, action needed

If you find issues:

• Segregate affected fish (separate holding container)
• Don’t put back with healthy koi
• Consult koi vet before proceeding

Step 3: Modified Cleaning for Koi Ponds

Key differences from goldfish pond cleaning:

Water saving:

• Save 50% of pond water (vs. 25% for goldfish)
• More beneficial bacteria preservation
• Easier on koi when refilling

Cleaning pace:

• Take 25% longer than normal
• More thorough equipment inspection
• Extra care with liner (koi ponds often larger/deeper)

Sludge removal:

• Must be complete (koi produce more waste)
• Pay special attention to bottom drains
• Clean behind every rock and crevice

Equipment focus:

• Koi ponds need superior filtration
• Check all bio-media thoroughly
• UV must be fully functional
• Aeration must be strong

Step 4: Refill with Koi-Safe Water

Critical difference: Water chemistry matters more for koi.

Refill process:

1. Temperature match within 2°F (not 5°F like goldfish)
2. Heavy dechlorination (koi need more)
3. KH buffer if needed (stabilize pH)
4. Slow refill (allows chemistry to stabilize)

Water additives for koi:

• Dechlorinator: Seachem Prime (best for koi) – double dose
• Stress coat: API Pond Stress Coat Plus – adds slime coat
• Salt: 0.1-0.3% (1-3 lbs per 100 gallons) – ONLY if koi are stressed
• Beneficial bacteria: Triple dose for koi ponds

About salt:

• Reduces stress
• Supports slime coat
• Helps osmoregulation
• BUT: Don’t use if you have plants
• Remove with water changes over 2-3 weeks

Step 5: Koi Acclimation (Extended Protocol)

Goldfish acclimation: 30-40 minutes Koi acclimation: 60-90 minutes minimum

Why longer for koi:

• More sensitive to temperature swings
• More valuable (can’t risk losses)
• Larger bodies = longer temperature equilibration
• Stress response more severe

Extended acclimation process:

Phase 1: Temperature matching (30 minutes)

• Float containers in pond
• Check temps every 10 minutes
• Don’t rush this

Phase 2: Water chemistry mixing (30 minutes)

• Add 1 gallon pond water to holding container
• Wait 10 minutes
• Add another gallon
• Wait 10 minutes
• Add another gallon
• Wait 10 minutes

Phase 3: Final preparation (10 minutes)

• Net should be in water, not air
• One person per koi (for large fish)
• Release area selected (calm, deeper spot)

Phase 4: Release (slow and careful)

• Lower net into pond
• Let koi swim out voluntarily
• Don’t dump or drop
• Watch for immediate stress signs

Post-release observation:

• Watch for 15-20 minutes
• Normal: Koi explores, swims calmly
• Concerning: Erratic swimming, gasping
• Critical: Floating, unable to swim

Post-Cleaning Koi Care (Critical First 30 Days)

The cleaning is done. Your work is just beginning.

Week 1: The Danger Zone

Days 1-2: NO FEEDING

• Even if water is 55°F
• Even if koi look hungry
• Let their systems recover from stress

Days 3-4: Observation Only

• Watch behavior 2-3 times daily
• Check for disease symptoms
• Test water daily
• Add beneficial bacteria

Days 5-7: Feeding Restart (SLOWLY)

The koi feeding restart protocol:

Only if water is 50°F+ and koi are active:

Day 5:

• Feed 1-2 pellets per koi
• Low-protein food (32% or less)
• Once per day only
• Watch for 2 hours (any regurgitation?)

Day 6:

• If Day 5 went well, feed 3-4 pellets per koi
• Same low-protein food
• Still once daily

Day 7:

• Feed 5-7 pellets per koi
• Monitor closely

Common mistake: Too much food too soon = ammonia spike + sick koi

Week 2: Gradual Increase

Water temperature guide:

50-55°F:

• Feed once daily
• 50% of normal amount
• Low-protein food (32%)

55-60°F:

• Feed once or twice daily
• 75% of normal amount
• Can switch to spring/fall food (35-38% protein)

60-65°F:

• Feed twice daily
• Normal amounts
• Regular protein (38-42%)

Over 65°F:

• Feed 2-3 times daily
• Full summer portions
• High-protein growth food (40-45%)

Critical rule: If water drops below 55°F due to cold snap, reduce feeding immediately.

Week 3-4: Disease Watch

This is when problems appear.

Spring diseases to watch for:

Spring Viremia of Carp (SVC)

• Lethargy, loss of balance
• Red spots on skin and fins
• Bloating, bulging eyes
• Appears at 50-60°F (prime spring temp)
• Action: Quarantine immediately, call vet

Aeromonas (Bacterial infection)

• Red ulcers on body
• Fin rot (ragged edges)
• Red streaks on fins/body
• Action: Salt bath, antibiotics, vet consultation

Costia/Chilodonella (Parasites)

• Flashing (rubbing on rocks)
• Excess slime production
• Lethargy, clamped fins
• Action: Microscope examination, targeted treatment

Anchor worm

• Visible thread-like protrusions
• Red, inflamed attachment points
• Koi scratching/flashing
• Action: Manual removal + treatment

Daily inspection routine (Weeks 3-4):

• Morning: Quick visual check (5 minutes)
• Evening: Thorough observation (15 minutes)
• Look for: behavior changes, flashing, isolation, feeding response
• Test water: Every 3 days minimum

Water Quality Standards for Koi (Higher Than Goldfish)

Koi need better water quality. Period.

Target Parameters (Spring)

 

Parameter	Goldfish OK	Koi Required
Ammonia	<0.5 ppm	0 ppm (zero)
Nitrite	<0.5 ppm	0 ppm (zero)
Nitrate	<80 ppm	<40 ppm
pH	7.0-8.5	7.2-7.8
KH	60+ ppm	100-150 ppm
Temperature	50-85°F	60-75°F optimal

Why koi need tighter parameters:

• Higher metabolism = more sensitive to toxins
• Valuable investment = can’t afford losses
• Show quality considerations
• Larger size = more waste production

Spring Water Testing Schedule

Week 1 post-cleaning:

• Test daily: Ammonia, nitrite, pH
• Test every 3 days: Nitrate, KH

Weeks 2-3:

• Test every other day: Ammonia, nitrite
• Test weekly: pH, nitrate, KH

Week 4+:

• Test twice weekly: Full panel
• Monthly: Comprehensive test

Red flags (take action immediately):
🚨 Ammonia above 0.25 ppm
🚨 Nitrite above 0.25 ppm
🚨 pH below 7.0 or above 8.2
🚨 Rapid pH swings (more than 0.3 in 24 hours)

Equipment Requirements for Koi Ponds

Koi ponds need better equipment than goldfish ponds.

Minimum Filtration Standards

For koi, calculate based on:

• 1 koi (adult) = 250 gallons biofiltration capacity needed
• Example: 10 adult koi = 2,500 gallon biofilter minimum

Goldfish ponds: Can get away with undersized filtration Koi ponds: Cannot compromise

Spring Equipment Checklist

Biological filtration:
☐ Media is clean but not sterilized
☐ Flow rate adequate (500 GPH per 1,000 gallons minimum)
☐ Multiple chambers if possible
☐ Media type appropriate (ceramic, lava rock, bio-balls)

Mechanical filtration:
☐ Pre-filter or settlement chamber
☐ Easy access for cleaning
☐ Adequate size for koi waste

UV clarifier:
☐ Bulb replaced annually (non-negotiable for koi)
☐ Quartz sleeve cleaned thoroughly
☐ Proper wattage (minimum 8 watts per 1,000 gallons)
☐ Running 24/7 starting in spring

Aeration:
☐ Minimum 1 air stone per 500 gallons
☐ Heavy aeration near bottom drain
☐ Backup air pump available
☐ Check valves installed

Bottom drain (if you have one):
☐ Cleared of all debris
☐ Operating properly
☐ Connected to settlement chamber or filter

Koi pond upgrade recommendations:

• If you don’t have a bottom drain, consider adding one
• If filtration is undersized, upgrade before summer
• If UV is weak, upgrade wattage
• If aeration is minimal, double it

Common Spring Koi Pond Mistakes (Learn From Others)

Mistake #1: The $2,500 “I Fed Too Early” Disaster

Client: Oak Brook, April 2022

What happened:

• March 30: Water hit 48°F
• Owner fed koi “just a little”
• April 2: Cold snap, water dropped to 42°F
• Food sat in stomachs for 5 days, rotting
• April 7: Lost 4 koi to digestive shutdown

Total loss:

• 4 koi: $2,500 value
• Vet visits: $400
• Medications: $200
• Emotional distress: Priceless

Lesson: Wait for CONSISTENT 50°F+. One warm day isn’t enough.

Mistake #2: The “Quick Clean” That Killed a Champion

Client: Naperville, 2021

What happened:

• Owner rushed spring cleaning (2 hours total)
• Didn’t acclimate koi properly (15 minutes only)
• Temperature shock: 8°F difference
• Lost $3,000 champion koi to stress-induced septicemia

Lesson: Koi need 60-90 minute acclimation. Don’t rush because you’re tired.

Mistake #3: The “It’s Just Ich” That Wasn’t

Client: Wheaton, 2023

What happened:

• Owner saw white spots, assumed ich
• Treated with over-the-counter ich medication
• Actually was Costia (different parasite)
• Treatment made it worse
• Lost 6 koi before proper diagnosis

Total loss: $4,200 in fish + $600 in wrong medications

Lesson: Get professional diagnosis for any disease symptoms. Don’t guess.

Mistake #4: Skipping the Salt

Client: Glen Ellyn, 2024

What happened:

• Spring cleaning went perfectly
• But didn’t add salt to reduce stress
• Within 10 days: bacterial infection outbreak
• Could have been prevented with 0.2% salt

Cost: $800 in vet visits and antibiotics

Lesson: 0.1-0.3% salt post-cleaning is an insurance policy for koi.

When to Call Professionals for Koi Pond Cleaning

Real talk: Koi are expensive. Mistakes are costly.

You Should Hire Professionals If:

Your koi situation:

• Individual koi worth $500+
• Show-quality koi
• Breeding stock
• Koi over 24 inches (need expert handling)
• Total collection value over $5,000

Your pond situation:

• First koi pond (learning curve is expensive)
• Large pond (5,000+ gallons)
• Complex filtration system
• Bottom drain system
• Previous spring losses

Your experience level:

• Never done koi pond cleaning
• Uncomfortable handling large fish
• Unsure about disease identification
• No experience with koi health issues

The math:

• DIY risk: 2-5% mortality = $500-$1,500 loss
• Professional service: $795-1,195 with zero loss
• Which is actually cheaper?

Our Koi-Specific Spring Cleaning Service

What makes our koi service different:

Premium Koi Care Protocol

Individual koi handling:

• Trained in proper koi handling techniques
• Individual health inspection per fish
• Photo documentation of each koi
• Detailed health report provided

Koi-safe cleaning:

• Extended acclimation (60-90 minutes)
• Temperature matching within 2°F
• Heavy dechlorination and stress reduction
• Premium beneficial bacteria (koi-specific formula)

Disease screening:

• Visual parasite check on every fish
• Behavioral assessment
• Gill inspection (external)
• Referral to koi vet if issues found

Post-service support:

• 3 follow-up calls (Week 1, Week 2, Week 4)
• Free water testing for first month
• Disease hotline access
• Feeding restart guidance

Equipment focus:

• UV bulb replacement included
• Filter media assessment
• Biological filtration optimization
• Aeration system check

Investment protection:

• $2 million insurance coverage
• 20 years koi-specific experience
• Zero mortality record on healthy koi
• Written service guarantee

Koi Cleaning Pricing

Small koi pond (under 3,000 gallons): $745-895 Medium koi pond (3,000-6,000 gallons): $995-1,295 Large koi pond (6,000+ gallons): $1,295-1,895

Includes:

• Everything in standard cleaning
• Plus koi-specific care protocol
• Plus individual fish assessment
• Plus extended post-service support

📞 (630) 407-1415 – Koi specialist available | 📧 hello@midwestpondfeatures.com | 🌐 www.midwestpondfeatures.com/koi-cleaning

Serving Chicago & suburbs with koi expertise since 2005

Frequently Asked Questions (Koi-Specific)

When can I start feeding my koi after a Chicago winter?

When water is CONSISTENTLY 50°F+ for 3-5 days. In Chicago, this is typically April 15-25. Start with tiny amounts (1-2 pellets per koi) and use low-protein food (32%). Gradually increase over 2-3 weeks. Feeding too early causes digestive shutdown and death.

Do I need to clean my koi pond differently than a goldfish pond?

Yes, significantly different.

Koi need:

(1) Longer acclimation time (60-90 min vs. 30-40 min),
(2) Individual health inspections,
(3) More careful handling,
(4) Better water quality standards,
(5) Extended post-cleaning observation.
Koi are more valuable and more sensitive; they require professional-level care.

How do I know if my koi have parasites after winter?

Watch for: Flashing (rubbing on rocks), excess slime production, lethargy, clamped fins, rapid gill movement, isolation from other fish, loss of appetite. If you see ANY of these signs, don’t guess call a koi vet for microscope examination. Wrong treatment kills fish.

Should I add salt to my koi pond after spring cleaning?

Yes, 0.1-0.3% salt (1-3 lbs per 100 gallons) is recommended for stress reduction post-cleaning. Salt supports slime coat production, reduces stress, and helps osmoregulation. Remove gradually over 2-3 weeks via water changes. Don’t use it if you have live plants or if koi have been treated with formalin recently.

My koi survived winter, but now they’re dying in spring. Why?

Spring is the most dangerous time for koi.

Common causes:

(1) Feeding too early/too much (digestive shutdown),
(2) Disease outbreak (suppressed immune system),
(3) Temperature shock during cleaning,
(4) Water quality crash (biological filter not established),
(5) Parasite infestation (parasites activate at 50-60°F).

Get professional help immediately.

How much does koi pond spring cleaning cost?

DIY: $500-800 equipment + 10-14 hours + risk of losses
Professional: $745-1,895 depending on size and koi count

Risk analysis: If you have $3,000+ in koi and DIY mortality rate is 3-5%, you risk $90-150 in losses. Professional service eliminates this risk. For valuable koi collections, professional service is actually cheaper when you factor in risk.

Can I clean my koi pond in March to get ahead of the season?

This kills koi. Wait until water is consistently 50°F+ (usually mid-April in Chicago).

Cleaning too early causes:

(1) Severe temperature stress,
(2) Compromised immune response,
(3) Inability to handle cleaning stress,
(4) Higher mortality rate. Patience saves lives.

Your Koi Spring Checklist

Print this and follow exactly:

3-4 Weeks Before Cleaning (Late March)

☐ Start monitoring water temperature daily
☐ Observe koi behavior as they wake up
☐ Order supplies (dechlorinator, bacteria, food)
☐ Check equipment functionality
☐ Schedule professional service if using

Week Before Cleaning

☐ Confirm water temp 50°F+ for 3-5 days
☐ Test baseline water quality
☐ Set up fish holding area
☐ Prepare health inspection station
☐ Review disease symptom guide

Day of Cleaning

☐ Individual koi health inspection
☐ Photograph each koi
☐ Document any abnormalities
☐ Save 50% of pond water
☐ Thorough sludge removal
☐ Complete equipment service
☐ Koi-safe refill (temp matched within 2°F)
☐ Heavy dechlorination + stress coat
☐ Triple dose beneficial bacteria
☐ 60-90 minute acclimation
☐ Gentle release and observation

Week 1 Post-Cleaning

☐ NO FEEDING days 1-2
☐ Test water daily (ammonia, nitrite, pH)
☐ Observe koi 2-3 times daily
☐ Day 3-4: Add more bacteria
☐ Day 5: Start feeding (1-2 pellets per koi)
☐ Gradually increase feeding

Weeks 2-4

☐ Monitor for disease symptoms daily
☐ Test water every 2-3 days
☐ Gradually increase feeding to normal
☐ Watch for parasites (flashing, clamped fins)
☐ Document any concerns

The Bottom Line on Koi Spring Care

Koi are not goldfish.

They’re more valuable. More sensitive. More rewarding when healthy. More devastating when lost.

Spring is when most koi deaths occur not because of winter, but because owners rush the spring process.

Follow this guide exactly:

• Wait for 50°F+ consistently (don’t rush)
• Inspect every fish individually
• Acclimate for 60-90 minutes minimum
• Start feeding slowly (days 5-7)
• Monitor obsessively for first 30 days

Or hire professionals who’ve done this 1,000+ times and know exactly how to protect your investment.

Either way, respect the spring danger zone. Your koi just survived a Chicago winter and now give them the spring care they need to thrive all season.