Floating aquarium plants: which ones to choose and why?
Often overlooked in favour of substrate plants, floating plants actually do a lot for a tank's balance while giving shy fish a natural hiding spot. Here are the best species to choose and the benefits they bring. The toys and enrichment category gathers all our decor guides.
What benefits do floating plants bring?
Beyond absorbing some of the nutrients dissolved in the water, they filter surface light, which reassures skittish species and limits algae growth on the glass by reducing the light available to them.
Which species suit your setup?
- Duckweed (Lemna minor): very fast-growing and excellent at soaking up excess nutrients, but needs thinning regularly since it can quickly cover the entire surface.
- Water lettuce (Pistia): substantial roots that fry appreciate, best suited to tanks tall enough to give the roots room.
- Salvinia: small and easy to remove when it spreads, tolerates a wide range of water parameters.
- Azolla: moderate growth, adds a reddish decorative touch depending on lighting.
How do you stop them from taking over the tank?
Regularly netting out the excess, using the same care as any handling described in our guide to stress-free fish handling, keeps a partial cover rather than a full mat that would starve bottom plants of light.
Do these plants really cut down on nitrates?
A study by Cedergreen and Madsen, published in 2002 in New Phytologist, shows that duckweed absorbs dissolved nitrogen efficiently, with a marked preference for ammonium over nitrate, making it a natural ally for smoothing out nitrogen spikes between water changes (study on Google Scholar). This mechanism complements, without replacing, the regular maintenance covered in our nitrogen cycle guide.
Frequently asked questions
Do floating plants suit a betta tank?
Absolutely, they filter the light and provide resting points that this surface-breathing species appreciates.
Do these plants need special lighting?
No, most do fine under standard aquarium lighting, with no special requirements unlike some substrate plants.
Can you keep them with herbivorous fish?
Yes, but herbivorous fish may nibble the roots, so plan for a wider cover to compensate. Browse all our guides on the fish hub.
This guide is part of Planète Pets’s Fishkeeping universe. Our advice is general in nature: for any health concern, your veterinarian remains the only reference.