Koi Pond Design, Construction & Installation – Gauteng
Subtropical Garden & Pool Services cc design, supply and install high-quality koi ponds for residential and commercial clients in Randburg, Roodepoort, Midrand, Sandton, Centurion, Pretoria and Johannesburg.
A koi pond is a purpose-built water feature designed to house ornamental Japanese carp (koi). These ponds are deeper and structurally stronger than standard garden ponds, as koi grow large, live for decades, and require excellent filtration and water quality to thrive.
A professionally built koi pond instantly transforms a garden into a tranquil, elegant space. With graceful koi gliding through crystal-clear water and the calming sound of a waterfall, a koi pond becomes the focal point of your outdoor environment — promoting peace, relaxation and natural beauty.
Interested in a Koi Pond?
📞 Get a Free Quotation
📞 Call: 083-560-1555
📩 Request a quotation online
🌿 Local, trusted outdoor services since 1995
Request your quotation today and we will get in touch to arrange a site visit and provide expert recommendations tailored to your garden.
Key Considerations When Building a Koi Pond
✅ Size & Depth
Koi require ample space to swim and grow.
We recommend a minimum depth of 1.2m–1.5m (4–5 ft), with larger ponds preferred for growth and potential breeding.
✅ Location
Choose a location with balanced sunlight and shade to regulate water temperature and reduce algae.
Avoid areas with large trees to limit leaves falling into the pond.
✅ Filtration System
Filtration is critical to koi health.
We install robust systems including skimmers, settlement chambers, bottom drains, UV clarifiers and biological filtration to keep water clean and healthy.
✅ Safety
We ensure your pond is designed to:
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Prevent koi from jumping out
-
Deter predators like birds and cats
-
Include protective netting if children have access to the area
✅ Aesthetic Design
From formal contemporary ponds to natural “river-style” koi habitats, we design ponds to complement your garden style and architecture.
✅ Maintenance
We provide maintenance advice and support — koi ponds require regular care, including water testing, filter cleaning and monitoring fish health.
Why Choose a Koi Pond?
| Benefit | Description |
|---|---|
| Longevity & Growth | Koi can live for decades and grow impressively large with proper care |
| Relaxation & Ambience | Flowing water and colourful fish promote calmness and reduce stress |
| Statement Feature | A professionally designed pond becomes a stunning garden centrepiece |
| Cultural Symbolism | Koi represent luck, prosperity, perseverance, love and harmony |
Bring Your Garden to Life
A koi pond is a rewarding investment that enhances your garden’s beauty and ambience — but correct planning and installation are essential for healthy fish and long-term success.
Let our experienced team design and build the perfect koi environment for your home or business.
Interested in a Koi Pond?
Request your quotation today and we will get in touch to arrange a site visit and provide expert recommendations tailored to your garden.
Why a Well-Designed Koi Pond Matters
Many homeowners assume a koi pond is simply a hole that holds water — but building a successful koi pond is far more complex. Without careful planning and professional design, a pond can quickly become a disappointment: poor water quality, sick fish, excessive maintenance and ongoing repairs are common problems when design details are overlooked.
The real issue is that there is no one-size-fits-all solution. Advice from friends or forums can be well intentioned but often contradictory — and what worked for one pond won’t necessarily work for another. Pond performance depends on size, depth, filtration, circulation, local climate, planting, site placement and long-term maintenance. For these reasons, a properly designed koi pond needs to be tailored to your garden, your fish and your lifestyle.
If you’d like expert guidance and a pond built right the first time, please complete the Request My Quotation form below. We’ll arrange a site visit, assess your requirements and provide a detailed, professional quotation.
Why Hire a Professional?
-
Correct sizing & depth — prevents temperature swings and supports healthy growth
-
Right filtration & circulation — keeps water crystal clear and fish healthy
-
Site-specific design — considers sun, shade, runoff and debris sources
-
Predator protection & safety — protects fish and family alike
-
Long-term support — commissioning, seasonal maintenance and troubleshooting
The three essential requirements for building a successful koi pond are:
1. Superior Water Quality
Clear water alone does not guarantee a healthy environment. A truly successful koi pond must support excellent water quality that promotes the health and vitality of the fish. Without proper filtration and water management, koi owners may find themselves constantly battling disease and stress in their fish.
2. Effective Predator Protection
The pond must be designed to keep koi safe from predators. Simply providing a “deep spot” for fish to hide is not enough. The entire pond should be deep and contoured in a way that discourages predators from attempting to hunt in the pond in the first place.
3. Ease of Maintenance
A well-designed koi pond should be easy to manage and maintain. Poorly planned ponds often become labor-intensive and frustrating to care for, turning what should be a relaxing hobby into a demanding chore.
What a Successful Koi Pond Needs
A successful koi pond must be designed to support healthy koi, clear water, and effortless maintenance. Crystal-clear water is essential — not only for the health of your koi, but also to fully enjoy their colour and beauty. Proper filtration, aeration, and pond depth ensure water stays clean and balanced year-round.
Koi also need a safe environment free from predators. A well-built pond provides safe depth and structure so koi can thrive naturally without nets or constant worry.
Maintenance should be simple. With the right pond design and filtration system, even a large koi pond can require less than five minutes of upkeep per week, giving you more time to relax and enjoy your water garden.
Key koi pond essentials:
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Deep pond design (minimum 1.2m) for koi health and predator protection
-
Advanced mechanical & biological filtration for crystal-clear water
-
Proper sunlight balance and smart placement for ideal viewing and water stability
-
Efficient plumbing & maintenance features for easy cleaning and long-term reliability
Build your koi pond right from the start — and enjoy a beautiful, low-maintenance water feature that keeps your koi healthy, safe, and thriving.
Interested in a Koi Pond?
📞 Get a Free Quotation
📞 Call: 083-560-1555
📩 Request a quotation online
🌿 Local, trusted outdoor services since 1995
Request your quotation today and we will get in touch to arrange a site visit and provide expert recommendations tailored to your garden.
✅ 20 Questions to Answer Yourself Before Building a Koi Pond (With Full Answers)
1. How large should I make my pond?
Bigger is better for koi health, water stability, and future growth.
Minimum size: 10,000 litres (≈ 2,600 gallons)
Ideal for hobbyists: 15,000–30,000 litres
Koi grow large and live for decades — build for the future, not just today.
2. Where should I place my pond?
Choose a location that offers:
-
Partial sunlight (avoid full, all-day sun)
-
Good visibility from your home or patio
-
Easy access for maintenance and filtration
Avoid placing under large trees (leaves = debris problems).
3. Can I grow plants in my pond?
Yes — but koi will eat or uproot many plants.
If you want plants, consider:
-
A dedicated plant zone separate from koi
-
Floating islands or shallow plant shelves
-
Strong plant species like lotus and water lilies
4. Which pond is better — rubber liner or concrete pond?
| Rubber Liner | Concrete / Fibreglass |
|---|---|
| Lower cost | Highest durability |
| Flexible shapes | Clean professional finish |
| Risk of puncture | Long-term investment |
For serious koi keepers: Concrete with fibreglass finish is ideal.
5. How important is shape and contour?
Very important — koi ponds work best when designed like a smooth bowl with sloped sides and no shelves.
This prevents debris buildup and improves water flow to bottom drains.
6. How deep should I make the pond?
Minimum: 1.2 m (4 feet)
Recommended: 1.5–2 m (5–6.5 feet)
Depth protects koi from predators & temperature swings.
7. How important is the filter?
Absolutely essential.
A koi pond is only as good as its filtration system:
-
Mechanical: Removes solids
-
Biological: Breaks down ammonia & nitrites
-
Optional UV: Controls green-water algae
8. How far away from the pond can I install the filter?
Typically within 3–10 metres, depending on plumbing and pump strength.
Further is possible with correct pipe sizing and pump planning.
9. Do I need a pre-filter?
Yes — a pre-filter removes heavy waste before it reaches the main biological filter.
Best options:
-
Sieve filters
-
Drum filters
-
Settlement chambers
Pre-filters reduce cleaning and improve water clarity dramatically.
10. What size pump will I need?
Turn over the full pond volume once every 1–2 hours.
Example: 20,000-litre pond → 10,000–20,000 L/hr pump
Choose an energy-efficient pump — it runs 24/7.
11. What size pipe should I use?
Bigger is better for flow and efficiency:
-
Bottom drains: 110mm
-
Pump suction/returns: 50–63mm
Undersized pipes = reduced flow + more maintenance.
12. How important is a bottom drain?
Critical for koi ponds.
Bottom drains:
-
Remove fish waste & debris
-
Improve circulation
-
Reduce cleaning and sludge buildup
Never rely only on pumps inside the pond — they clog and stress fish.
13. How important is a skimmer?
Very important — removes floating leaves, dust, foam, food and oils.
Keeps surface clean and increases oxygen exchange.
14. How important are jets (return flow nozzles)?
Essential for proper circulation.
They push waste toward the bottom drain and prevent dead zones.
15. How important is an auto-fill system?
Recommended.
Koi ponds lose water to evaporation and backwash.
Auto-fill saves time and maintains stable water levels.
16. Do I need a UV light?
Highly recommended for clear water.
UV sterilizers kill free-floating algae (green water) and help control harmful bacteria.
Size UV to pond volume & flow rate.
17. Should I install underwater pond lights?
Optional but beautiful!
Use:
-
Low-voltage LED lighting
-
Waterproof fittings
-
Warm colour light for natural koi colour
Don’t over-light — koi rest better with darker nights.
18. Do I need an automatic koi feeder?
Optional but very useful if you’re away often.
Benefits:
-
Consistent feeding schedule
-
Better growth & water quality
-
No overfeeding mistakes
19. How many koi can I put in my pond?
Rule of thumb:
1 koi per 1,000 litres minimum
Better long-term: 1 koi per 2,000 litres
Overstocking = stress, disease, high maintenance
20. What should I look for in a koi pond builder?
Choose a specialist who understands koi systems, not just garden water features.
Verify they have experience with:
-
Bottom drains & gravity-flow systems
-
Proper filtration sizing
-
Correct depth & layout
-
Previous koi pond projects
Ask for references, photos, and a maintenance plan.
✅ 20 Questions to Answer Before Building a Koi Pond (With Full Answers)
1. How large should I make my pond?
Bigger is better for koi health, water stability, and future growth.
Minimum size: 10,000 litres (≈ 2,600 gallons)
Ideal for hobbyists: 15,000–30,000 litres
Koi grow large and live for decades — build for the future, not just today.
2. Where should I place my pond?
Choose a location that offers:
-
Partial sunlight (avoid full, all-day sun)
-
Good visibility from your home or patio
-
Easy access for maintenance and filtration
Avoid placing under large trees (leaves = debris problems).
3. Can I grow plants in my pond?
Yes — but koi will eat or uproot many plants.
If you want plants, consider:
-
A dedicated plant zone separate from koi
-
Floating islands or shallow plant shelves
-
Strong plant species like lotus and water lilies
4. Which pond is better — rubber liner or concrete pond?
| Rubber Liner | Concrete / Fibreglass |
|---|---|
| Lower cost | Highest durability |
| Flexible shapes | Clean professional finish |
| Risk of puncture | Long-term investment |
For serious koi keepers: Concrete with fibreglass finish is ideal.
5. How important is shape and contour?
Very important — koi ponds work best when designed like a smooth bowl with sloped sides and no shelves.
This prevents debris buildup and improves water flow to bottom drains.
6. How deep should I make the pond?
Minimum: 1.2 m (4 feet)
Recommended: 1.5–2 m (5–6.5 feet)
Depth protects koi from predators & temperature swings.
7. How important is the filter?
Absolutely essential.
A koi pond is only as good as its filtration system:
-
Mechanical: Removes solids
-
Biological: Breaks down ammonia & nitrites
-
Optional UV: Controls green-water algae
8. How far away from the pond can I install the filter?
Typically within 3–10 metres, depending on plumbing and pump strength.
Further is possible with correct pipe sizing and pump planning.
9. Do I need a pre-filter?
Yes — a pre-filter removes heavy waste before it reaches the main biological filter.
Best options:
-
Sieve filters
-
Drum filters
-
Settlement chambers
Pre-filters reduce cleaning and improve water clarity dramatically.
10. What size pump will I need?
Turn over the full pond volume once every 1–2 hours.
Example: 20,000-litre pond → 10,000–20,000 L/hr pump
Choose an energy-efficient pump — it runs 24/7.
11. What size pipe should I use?
Bigger is better for flow and efficiency:
-
Bottom drains: 110mm
-
Pump suction/returns: 50–63mm
Undersized pipes = reduced flow + more maintenance.
12. How important is a bottom drain?
Critical for koi ponds.
Bottom drains:
-
Remove fish waste & debris
-
Improve circulation
-
Reduce cleaning and sludge buildup
Never rely only on pumps inside the pond — they clog and stress fish.
13. How important is a skimmer?
Very important — removes floating leaves, dust, foam, food and oils.
Keeps surface clean and increases oxygen exchange.
14. How important are jets (return flow nozzles)?
Essential for proper circulation.
They push waste toward the bottom drain and prevent dead zones.
15. How important is an auto-fill system?
Recommended.
Koi ponds lose water to evaporation and backwash.
Auto-fill saves time and maintains stable water levels.
16. Do I need a UV light?
Highly recommended for clear water.
UV sterilizers kill free-floating algae (green water) and help control harmful bacteria.
Size UV to pond volume & flow rate.
17. Should I install underwater pond lights?
Optional but beautiful!
Use:
-
Low-voltage LED lighting
-
Waterproof fittings
-
Warm colour light for natural koi colour
Don’t over-light — koi rest better with darker nights.
18. Do I need an automatic koi feeder?
Optional but very useful if you’re away often.
Benefits:
-
Consistent feeding schedule
-
Better growth & water quality
-
No overfeeding mistakes
19. How many koi can I put in my pond?
Rule of thumb:
1 koi per 1,000 litres minimum
Better long-term: 1 koi per 2,000 litres
Overstocking = stress, disease, high maintenance
20. What should I look for in a koi pond builder?
Choose a specialist who understands koi systems, not just garden water features.
Verify they have experience with:
-
Bottom drains & gravity-flow systems
-
Proper filtration sizing
-
Correct depth & layout
-
Previous koi pond projects
Ask for references, photos, and a maintenance plan.