Aquatic plants A-Z: Alternanthera

Where's it from?

It originates from the tropical and subtropical open forests in Central and South America, think Amazon. They're often submerged when the riverbank floods, so they've adapted to both being fully submerged or out of the water.

So, what's it like?

It's red! One of the few true red aquascaping plants, it's super popular because of the contrasts in colour you can achieve with the rest of your tank. 

Varieties we stock


This plant has a fab purply/red underneath to the leaves, but provide it with good light and CO2 for an extra vibrant pop of colour. Cardinalis is vigorous, robust, and tolerates strong water movement well. It grows between 25-50cm tall, making for a good middle tank plant that adds lots of interest to your scape. It also tolerates a little overcrowding, if you like your tank FULL. 


Photo from Tropica

This miniature version is (obviously!) compact and has a slower growth rate. It is perfect for smaller scapes, or as a foreground plant in larger tanks. Look after it and trim it carefully, and you'll end up with a dense carpet of colour about 5-10cm high. Again, if you give it good intensity of light, and add CO2, it'll will help it grow and look stunning.

How quickly does it grow?

Alternanthera is slower growing compared to other stemmed plants and you can keep the mini version super compact if you want to. Because it's slow growing, it is definitely more forgiving when it comes to nutrients or CO2, but if you want it to be super red don't skip this part!

How do I trim it?

Try not to uproot it and replant it, you'll get much better results by trimming the tops of the plants. It's a bit scary chopping off the healthy tops of your plants, but trust us, it'll soon sprout new side shoots and you'll get a nice bushy plant over time. You can always replant the cut top somewhere else too - free bonus plant!

What lighting is best?

Good lighting helps it's red colouration. The better the lighting, the better density of leaves too - but we'll leave you to juggle that part, as it's worth noting that algae likes Alternanthera. 

How do I make it more red?

Stronger lighting will definitely help, go higher on the red/blue spectrum. A good system in place for fertilisation helps too, and keep it consistent. 

Care level

Whilst not a massively demanding plant, it mostly suffers because we try and do too much rather than too little. Don't change too many variables frequently, you're going for a sustained period of stability for this one. Get it right though and you'll have a riot of colour. Go forth, and paint the town scape red! 

Surprise bonus!

Remember back at the beginning when we said it was happy in and out of water? Alternanthera works well in a terrarium too! Here it is in a DOOA Neo Glass Air looking utterly fabulous, we're in love.

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