Floating aquatic plants provide natural filtration, shade, and surface coverage for ponds and water gardens. Their roots absorb excess nutrients directly from the water, helping improve water quality and reduce nutrients available for algae growth. Floating plants also provide shelter and natural grazing opportunities for pond fish.
Benefits of floating aquatic plants
- Natural filtration: Floating plants absorb excess nutrients, including nitrogen and phosphorus, helping maintain water quality.
- Algae control: Floating leaves provide shade, reducing sunlight available for algae growth.
- Water temperature regulation: Surface coverage helps shade pond water during hot weather.
- Fish protection: Floating roots provide shelter for small fish and newly hatched fish (fry).
- Natural fish food: Fish may nibble on floating plant roots, providing an additional source of natural forage.
- Improved appearance: Floating plants add greenery, texture, and seasonal interest to ponds.
Popular floating aquatic plants
Water hyacinth (Pontederia crassipes, formerly Eichhornia crassipes)
- Features glossy green leaves and attractive purple flowers.
- Absorbs excess nutrients from pond water.
- Grows and reproduces rapidly in warm conditions.
- Typically grown as an annual in colder climates.
Water lettuce (Pistia stratiotes)
- Features soft, light-green leaves arranged in floating rosettes.
- Provides shade and shelter for small fish.
- Absorbs nutrients through its submerged root system.
- Grows best in warm, protected water.
Will fish eat the roots of floating plants?
Yes. Koi and goldfish may nibble on the roots of floating aquatic plants. Occasional grazing is generally harmless, and healthy, fast-growing plants can often replace damaged roots.
- Natural grazing: Floating plant roots provide opportunities for fish to forage.
- Plant regrowth: Fast-growing floating plants can often recover from minor root damage.
- Waterlily protection: Floating plants may provide an alternative grazing source, although they will not necessarily prevent fish from damaging waterlilies.
- Excessive grazing: Large or active fish may damage roots faster than plants can recover.
If fish are repeatedly damaging floating plants, consider protecting the plants in a floating plant basket or separating them from areas with heavy fish activity.
Floating plants should supplement, not replace, a nutritionally complete pond fish diet.
How to care for floating aquatic plants
- Placement: Place plants directly on the pond's surface, away from strong waterfall currents and skimmer openings.
- Sunlight: Provide suitable sunlight based on the plant species.
- Growth control: Remove excess plants regularly to prevent overcrowding.
- Skimmer protection: Keep floating plants away from skimmers to prevent blockages and maintain proper water circulation.
- Winter care: Water hyacinth and water lettuce are tropical plants that generally cannot survive freezing conditions. Remove them before winter in colder climates.
Important considerations
Floating aquatic plants reproduce quickly and can cover large portions of a pond if left unmanaged. Excessive surface coverage may limit sunlight reaching submerged plants and interfere with gas exchange at the water's surface.
Water hyacinth and water lettuce are invasive or regulated in certain areas. Check local and state regulations before purchasing or growing these plants.
Never release floating aquatic plants into natural waterways. Dispose of unwanted plants responsibly according to local regulations.