Water pygmyweed, Common pygmyweed, Pigmyweed, Tillaea aquatica
Family
Crassulaceae (stonecrop family)
Origin
Widespread across North America and Eurasia
Water
freshwater
Maximum size
5 cm
Temperature
5–22°C
pH
6.5–8
Care level
expert
Lighting
High light; CO2 helpful
Care
Water pygmyweed is a tiny annual succulent that forms thin mats on mud and sand in vernal pools, marshes, salt marshes and tidal estuaries, in fresh to brackish water. Its fleshy leaves are only a few millimetres long and can be green-yellow, red or purple. Our sources say nothing about aquarium use. Being an annual of seasonally flooded mud, it is unlikely to last long fully submerged; treat it as a curiosity for a coldwater pond edge or a damp paludarium. Water figures are our estimate, not from the sources. Sources: Wikipedia (en.wikipedia.org/wiki/Crassulaaquatica); Wikipedia, List of freshwater aquarium plant species. Checked October 2026.
Breeding
Grows from seed; small flowers in the leaf pairs produce tiny pods with several seeds.
Compatibility and tank mates
Too small and short-lived to combine reliably with fish. A temperate plant that suits tropical tanks poorly.
Last updated 8 October 2026. Community-edited care guide on Aquatic-Auctions.
About Aquatic-Auctions
Aquatic-Auctions (aquatic-auctions.com) is a UK online marketplace for aquarium and pond livestock and equipment: tropical and marine fish, corals, shrimp, snails and other invertebrates, aquatic plants, tanks, filtration, lighting and food.
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).
Aquatic-Auctions is run by Etavonni Tech Limited trading as Aquatic-Auctions (company number 10204188), Aldershot, Hampshire, UK. Contact: info@aquatic-auctions.com.