Hard-water Watermilfoil

Myriophyllum tetrandrum

Feathery bright green leaves on a red-brown stem — the watermilfoil for hard water, where most fine-leaved plants struggle.

Light: medium–high
Difficulty: medium
Temperature: 18 – 34 °C (64 – 93 °F)

Leaf colour: green, red +1 green, red, bronze or brown
Plant type: stem plant
Growth rate: medium
Tolerates light: medium – high
Carbonate hardness: 0 – 8 °dKH
Placement: background, midground
Propagation: cuttings
Grows emersed: yes

Appearance

Leaves cut into fine threads in whorls along a reddish stem, so the group shows green and red-brown at once. Planted in a bunch it makes a thick feathery bush.

Keeping

Moderate demands and unusually tolerant of hard water, which it actually prefers. Good light keeps it dense; carbon dioxide is not required. It grows quickly enough to shade its neighbours, so trimming is routine.

Placement

The middle or back of the tank, in a group — several stems together read as one soft mass, a single stem looks bare.

Propagation

By cuttings: replant the trimmed tops.

Water conditions match

The water suits 1016 of 1249 species in the catalogue — these are the ones people look up most often.

Swordtail Guppies Cobra Guppy Blood Red Molly Butterflyfish Red Zebra Cichlid Julii Corydoras Red-finned Parotocinclus Gastromyzon monticola Egg-shaped Goldfish Flame Tetra Gardner's Killifish African Tetra Kenyi Cichlid Cuckoo Catfish Golden Swordtail Hypsolebias picturatus Common Zacco Labeo Bicolor Gambusia Flying barb Gastromyzon scitulus Albino Zebra Danio Geophagus Brokopondo Zebra Mbuna

Will eat this plant

These species damage plants, especially when their diet is short of vegetable food.

Bengal Loach Zebra Loach Burmese Border Loach Emperor Botia Marbled Headstander Pellegrin's Leporinus Leporinus striatus False Black Tetra Common Metynnis Mylossoma duriventre Red Whiptail Catfish Molly sphenops Balloon Molly Lyretail Molly Marble Molly Hi-Fin Platy Hawaii Platy Blue Platy Pintail Platy Black Platy Chocolate Molly Moonlight Gourami Melanotaenia parva

Will uproot it

These species dig through the substrate and pull rooted plants out.

Marble Loach Peacock Eel Forktail Loach Guntea Loach Long-nosed Loach Horseface Loach Pearlscale Black Moor Goldfish Shubunkin Painted Pleco Featherfin Synodontis Reddish Mystus Catfish Blue Acara Aulonocara maylandi Aulonocara multicolor Aulonocara Orchid Geophagus altifrons Geophagus winemilleri Pearlscale Cichlid Pearl Cichlid Redbelly Cichlid Red-spotted Cichlid Chuco godmanni Haplochromis philander Red Chromide Jack Dempsey cichlid

Matching water does not mean the fish will leave the plant alone.

Scientific and other names, conservation status

Other scientific names: Myriophyllum indicum Wallich, Myriophyllum indicum tetrandrum, Myriophyllum pusillum
Myriophyllum tetrandrum: Roxb.
Family: Haloragaceae