Northern South America (Venezuela, Colombia, Guyana, Ecuador, Peru and northern Brazil)
Water
freshwater
Maximum size
40 cm
Temperature
24–28°C
pH
5.5–6.8
Hardness
Soft
Care level
expert
Lighting
Strong light; CO2 helpful
Care
Echinodorus horizontalis is a sword from northern South America, now called Aquarius horizontalis. Wikipedia now follows a 2018 revision that moves most swords out of Echinodorus into the genus Aquarius. Its leaves are 25–40 cm long, with blades about 10–17 cm by 5–8 cm held almost horizontally, which gives the plant its name. It grows emersed or submerged and needs a deep, rich substrate, strong light, soft and slightly acidic water and tropical temperatures. It is considered demanding and is now rarely seen in the hobby. Exact figures are our estimate, not from the sources. Sources: Wikipedia (en.wikipedia.org/wiki/Echinodorushorizontalis); Wikipedia, List of freshwater aquarium plant species. Checked October 2026.
Breeding
Mainly by plantlets that form on the flower stalk; let them root before cutting them free.
Compatibility and tank mates
Sword leaves are fairly tough, but large cichlids, goldfish and other diggers may uproot young plants or chew soft new leaves; root them well. Good with tetras, angelfish, discus and other tropical community fish. Snails may graze old leaves.
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.