Can I grow this in a freshwater tank?

No, it requires saltwater to survive.

Does it need high light?

Yes, it requires clear water and high light levels to photosynthesize.

Plant guide

Eelgrass.

Zostera marina

Pronounced zos-TEER-uh muh-REE-nuh

Also known as Common Eel-Grass, Common eelgrass, Eelgrass, Narrow-Leaved Eelgrass, Sea grass

Eelgrass is a fascinating marine flowering plant that thrives in shallow coastal waters. It forms dense underwater meadows that provide essential habitat for many sea creatures. You will mostly find this plant growing submerged in sandy or muddy marine environments.

At a glance

Care level: Difficult
Plant type: Aquatic perennial
Light: Full sun in natural habitat
Indoor light: Bright indirect
Water: Every 0 days
Mature size: 1 to 2 meters
Growth rate: Medium
Hardiness: USDA 4 to 9
Bloom time: Mid to late summer

Care

This plant requires specific salinity and water quality to thrive in an aquarium setting. Keep an eye on water clarity and sediment stability to ensure it stays anchored. It is best suited for advanced hobbyists with specialized marine setups.

Watering: This is a fully submerged aquatic plant that does not require watering.
Feeding: Use specialized marine substrate fertilizers if the nutrient levels in your tank are low.
Pruning: Trim away any decaying or damaged leaves to maintain water quality.
Repotting: Repot only if the root system becomes severely overcrowded in its container.
Soil: Sandy or muddy marine substrate
Soil pH: 7.5 to 8.5
Temperature: 0 to 25°C
Humidity: 90 to 100%

Safety

People: There is no known toxicity to humans.
Children: The long, ribbon like leaves can pose a minor entanglement hazard in shallow water.
Edibility: While not toxic, it is not considered a food source for humans and may contain high salt content.

How to identify it

Long, ribbon like green leaves
Grows in dense underwater meadows
Small, inconspicuous flowers
Roots anchor in sandy sediment

Height: 0.3 to 1m
Spread: 0.1 to 0.3m
Leaves: bright green, deciduous
Flowers: green, 0.5 to 1cm
Fruit: brown, Late summer to autumn

Problems to watch for

Algae OvergrowthCommon
Wasting DiseaseCommon

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Growing it

Propagation: division, seed
When to plant: spring, autumn

Maintain high water clarity to ensure all species in the meadow receive enough light.

Grows well with

Turtle grass · Both are seagrasses that form underwater meadows, though turtle grass grows in warmer tropical waters than eelgrass.

Similar species

Dwarf eelgrass · It is a smaller relative that occupies similar intertidal zones.

Science

Family: Zosteraceae
Genus: Zostera
Order: Alismatales
Class: Liliopsida
Native range: Northern Hemisphere coastal waters.
Conservation: It is protected in several regions due to the decline of seagrass meadows from water pollution.

It thrives in sheltered bays and estuaries where it anchors into sandy or muddy bottoms.

Value to wildlife: nursery for juvenile fish, stabilizes coastal sediment, carbon sequestration
Pollinators: beetles
Uses: coastal restoration, sediment stabilization, aquarium habitat

Through the year

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Flowering

Fruiting

Foliage

Ecological indicators

Salinity: 8/9
Soil reaction: 7/9
Light: 8/9
Temperature: 4/9
Moisture: 9/9
Nutrients: 5/9

Taxonomy resolved against GBIF.

Questions people ask

Can I grow this in a freshwater tank?: No, it requires saltwater to survive.
Does it need high light?: Yes, it requires clear water and high light levels to photosynthesize.

Where the name comes from

The genus name Zostera comes from the Greek word for belt, referring to its ribbon like leaves, while marina indicates its marine habitat.

Good to know

It is a true flowering plant, not a seaweed.
It forms vast underwater meadows that provide critical habitat.
It is a vital carbon sink, capturing carbon faster than many terrestrial forests.
The seeds are dispersed by water currents.

Keep your eelgrass growing

This page is a general guide. Save your plant in Pocket Botanist and you get care reminders timed for this plant, plus a care history that shows what worked.

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This guide was generated with AI on September 25, 2026 and checked against GBIF taxonomy. It is general information, not horticultural or veterinary advice. Read about how we build these guides.