Adding fish to a pond may seem like a natural choice, but is it always the best idea? While fish can bring movement and life to a water feature, they also come with environmental challenges. Whether you’re creating a backyard wildlife pond or restoring a natural wetland, it’s important to consider the impact fish will have on water quality, biodiversity, and ecosystem balance.
So, should you have fish in your pond? Let’s explore the pros, cons, and eco-friendly alternatives.
The pros of having fish in your pond
– Aesthetic Appeal & Relaxation
Watching fish swim through clear water can be calming and beautiful, adding a sense of serenity to your pond.
– Algae Control (in Some Cases)
Certain fish, like native gudgeons and rainbowfish, can help control algae by eating excess plant material. However, too many fish can actually make algae problems worse.
– Mosquito Control
Small native fish can help reduce mosquito larvae in standing water, making your pond more enjoyable in summer.
– Educational Value
For families or schools, keeping fish in a pond provides a great opportunity to learn about aquatic life and responsible pet care.
The cons of keeping fish in a pond
– Water Quality Issues
Fish produce waste, which increases ammonia and nitrate levels, leading to poor water quality and excessive algae growth. Without proper filtration and regular maintenance, fish ponds can become stagnant and unhealthy.
– Harm to Native Wildlife
Non-native fish like goldfish and koi can cause serious environmental damage if they escape into natural waterways. They outcompete native species, stir up sediment, and destroy aquatic plants (Australian Government Department of Environment, 2023).
– More Maintenance Required
Unlike natural ponds that mostly take care of themselves, fish ponds require:
- Filtration systems to remove waste
- Aeration to provide oxygen
- Regular water changes to prevent toxic buildup
– Predator Attraction
Fish can attract birds, cats, and other predators, which may disrupt the ecosystem or require additional protective measures like pond netting.
Eco-friendly alternatives
If you want a low-maintenance, wildlife-friendly pond, consider leaving out fish and focusing on native aquatic plants, insects, and amphibians.
1. Encourage frogs and tadpoles
– Natural mosquito control
– Improve pond biodiversity
– Require no feeding or filtration
Tip: Add shallow zones, floating plants, and native grasses to attract frogs.
2. Create a habitat for dragonflies
– Dragonfly larvae eat mosquito larvae
– Dragonflies are excellent pollinators
– Add rocks, reeds, and submerged plants for shelter
3. Use native aquatic plants for algae control
– Floating plants shade the water, reducing algae
– Rooted plants absorb excess nutrients, keeping water clean
– Examples: Water ribbons (Triglochin procera), nardoo (Marsilea drummondii), common rush (Juncus usitatus)
4. Add small native fish (only if needed)
If you really want fish, choose small, native species suited to your region. Some good options include:
- Southern pygmy perch (Nannoperca australis) – Found in southern Australia, good for ponds
- Pacific blue-eye (Pseudomugil signifer) – A great choice for Queensland and NSW ponds
- Australian smelt (Retropinna semoni) – Peaceful, schooling fish for larger ponds
– Native fish support local biodiversity
– Less risk of harming ecosystems compared to exotic species
– Still require care and maintenance
Final verdict: no fish for a healthy pond
If you want to create a natural, self-sustaining ecosystem, the best choice is no fish at all. Here’s why:
1. Fish disrupt natural ecosystems
- Fish eat dragonfly larvae, tadpoles, and aquatic insects, reducing biodiversity.
- They stir up sediment, leading to murky water and algae blooms.
- Fish waste increases nutrient levels, promoting excessive algae growth and poor water quality.
2. A fish-free pond supports more wildlife
Without fish, your pond can support:
– Frogs & tadpoles – Natural mosquito control and a key part of wetland ecosystems
– Dragonflies & damselflies – Their larvae are top predators of mosquitoes
– Aquatic insects & microfauna – Provide food for birds, frogs, and beneficial creatures
– Healthy native plants – Without fish disturbing roots, plants thrive and filter the water naturally
3. It’s lower maintenance & more sustainable
- No need for filters, pumps, or water changes.
- Water stays cleaner naturally with plants and microorganisms.
- It functions like a true wetland, balancing itself over time.
The best approach
Instead of fish, focus on:
– Native water plants – Help filter water and provide habitat.
– Shallow zones with logs & rocks – Create shelter for frogs and insects.
– Floating plants like nardoo – Shade the water and reduce algae naturally.
– Leaving nature to do its work – A well-designed pond will balance itself!
Ponds weren’t meant to have fish. In natural wetland ecosystems, fish aren’t present in small, still water bodies, and adding them harms biodiversity rather than enhancing it.
If you want a thriving, low-maintenance, and truly sustainable pond, ditch the fish and let nature take the lead. The result? A healthier, more balanced ecosystem—one that supports frogs, dragonflies, birds, and native plants without human interference.
A pond without fish isn’t just better for nature—it’s how ponds are meant to be.
Australian Government Department of Environment. (2023). Impact of Invasive Fish on Native Ecosystems. Retrieved from https://www.dcceew.gov.au/
Wetlands Australia. (2023). Creating Wildlife-Friendly Ponds. Retrieved from https://www.dcceew.gov.au/water/wetlands
Australian Museum. (2023). Native Fish for Backyard Ponds. Retrieved from https://australian.museum/