Widgeongrass (Ruppia maritima)
Care, watering, light and tips for Widgeongrass on Floravia.
Quick facts
- Family: Ruppiaceae
- Difficulty: Moderate care
- Watering: every 7 days
- Light: Partial shade
- Temperature: 10–30 °C
About Widgeongrass
Ruppia maritima, commonly known as 'småhavgras' in some regions, is a submerged aquatic plant that forms dense underwater meadows. Its slender stems and filiform leaves give it a delicate and ethereal appearance. It is ideal for brackish or saltwater aquariums, as well as for coastal ecosystem restoration.
Native range
Cosmopolitan, found in coastal and estuarine environments worldwide.
Care tips
Requires bright to very bright light for optimal growth, preferably direct sunlight or powerful LED lighting. Water should be brackish or saltwater, with a salinity between 5 and 30 PSU, and a slightly alkaline pH (7.5-8.5). It prefers sandy or silty substrates rich in nutrients. A common mistake is insufficient water circulation, which can lead to detritus accumulation and affect its health.
How to save a dying Widgeongrass
- Warning signs
- Pale, transparent, or disintegrating leaves; lack of growth or decay.
- First aid
- Check salinity (10-30 ppt) and temperature (15-25°C). Ensure dim light and sandy substrate.
- What kills it
- Abrupt changes in salinity/temperature, excessive direct light, turbid or polluted waters.
- Can it be saved?
- Yes, if you act quickly. Stabilize aquatic environment and remove competing algae.