Beaked tasselweed, or widgeon grass, is a thread-thin, grass-like water plant of brackish marshes, coastal lagoons and salty ditches around the world. It is a salt-tolerant plant rather than a true seagrass, growing from a shallow rhizome into colonies of slender, branching stems. It is one of the few rooted plants for brackish-water tanks, and also grows in fresh water. Plant it in a sandy substrate with good light; it does not like murky water or stagnant, airless substrate. It may be annual or perennial. The sources give no salinity figures. Water figures are our estimate, not from the sources. Sources: Wikipedia (en.wikipedia.org/wiki/Ruppiamaritima); Wikipedia, List of freshwater aquarium plant species. Checked October 2026.
Breeding
Spreads by its rhizome into colonies; divide established clumps. It also sets fruit that sprouts readily.
Compatibility and tank mates
Suits brackish tanks with mollies, gobies, glassfish and similar fish; plant-eating species such as scats will eat it. Waterbirds and fish eat its fruit in the wild.
Last updated 8 October 2026. Community-edited care guide on Aquatic-Auctions.
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Items are sold by auction, buy it now or classified advert, by hobbyist and business sellers in the UK.
Buyers pay sellers directly; Aquatic-Auctions does not hold the money. Hobbyist sellers must offer PayPal and may also take cash on collection. Business sellers take PayPal (required) or cash on collection, and bank transfer only once they have a seller rating of 50 out of 100, a company and pet-selling licence checked by Aquatic-Auctions, a bank account in the company's name, and bank details approved by Aquatic-Auctions.
Buyers are told to pay by PayPal Goods & Services, never PayPal Friends and Family, gift cards or crypto.
Live fish and other vertebrates must be sent by specialist live-animal couriers (for example APC Overnight or DX Express), never by Royal Mail. Some invertebrates and plants may go by Royal Mail Special Delivery or 1st Class within its rules.
Banned and invasive species (for example those on the GB invasive species lists) cannot be listed, and sellers must meet the site’s animal welfare standards.
Members must be 16 or over to buy (16 and 17-year-olds with a parent or guardian’s agreement); sellers must be 18 or over.
Business sellers show their address, company details and pet-selling licence to buyers. Seller ratings run from 0 to 100: +1 for each positive feedback, −1 for each negative.
The site includes a free community species wiki with care guides (water parameters, tank size, diet, temperament, breeding).
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