How to plan a koi pond, aquarium or water feature — without wasting money

Step 1: Decide what you actually want to achieve

This sounds obvious, but most buyers skip it. Are you building a serene garden feature you'll enjoy from the house? A serious koi-keeping setup for growing valuable fish? A statement architectural aquarium for your home or office? The answer changes almost every decision that follows.

• Lifestyle and relaxation: an ecosystem pond with planting, waterfall sounds, and goldfish or small koi. Lower maintenance, natural look, excellent value.
• Serious koi culture: a dedicated formal koi pond with concrete construction, multi-stage filtration, and room to grow championship-quality fish.
• Architectural statement: a custom built-in aquarium or formal water feature as a design centrepiece in a home or commercial space.
• Low-maintenance beauty: a pondless waterfall or water wall — the sound and movement of water with almost none of the ongoing work.

Step 2: Understand filtration before anything else

Filtration is the single most under-specified element in Australian pond installations. Most failed ponds and aquariums fail because of inadequate filtration — not bad fish, not bad luck. A pond without proper biological filtration is a slow-motion fish tragedy.

Read the complete filtration guide →

Step 3: Measure your space properly

Measure the total available footprint including buffer zones around the pond, access paths for construction machinery, and clearance from structures, trees, and boundaries. A pond that "technically fits" on paper can feel cramped and cause maintenance problems if surrounds are too tight. Allow at least 600mm of clear working space around every edge.

Step 4: Assess your site conditions honestly

• Soil type: clay-heavy soil retains moisture which can affect liner performance. Rocky sites add excavation cost significantly.
• Trees nearby: roots are the enemy of pond liners and concrete over time. Leaf fall adds to filtration load. Avoid building within 3m of established trees where possible.
• Slope: any slope requires levelling. A pond on an unlevel base will have uneven water lines and filtration problems.
• Access: can an excavator reach the site? If not, expect significant additional cost for manual excavation.
• Sun exposure: full-day sun increases algae growth and water temperature — both manageable with proper filtration, but worth planning for.

Step 5: Build one written brief before getting any quote

Include: project type, approximate dimensions, depth requirement, filtration specification, construction method preference (liner vs concrete), any waterfall or landscape elements, fish stocking intentions, and your budget band. Send the identical brief to every installer you approach. Without this, you cannot meaningfully compare what you receive back.

Use our quiz to build your brief →