Having some red in the Fireplace Aquarium gives some nice contrasting colours. I picked up some AquaFleur Rotala rotundifolio ‘Blood red’ to see how that would do.
Red aquarium plants
There are lots of good choices to provide some red colour in a planted aquarium. I had very good success previously with Ludwigia palustris mini ‘Super Red’ which grew as an intense dark red but is a fast-growing stem plant that requires a lot of trimming. Another classic choice are various Alternanthera varieties. I have tried many including Alternanthera reineckii ‘Rot’, Alternanthera reineckii ‘Mini’, Alternanthera reineckii ‘Rosanervig’ and most lately Alternanthera cardinalis variegata. Unfortunately, amano shrimp think Alternanthera species are delicious, which is problematic for these plants. I also had a go with Cryptocoryne wendtii ‘flamingo’ which is supposed to be spectacular, but for me was pretty much just dark green. Cryptocoryne petchii ‘Pink’ also didn’t really pink up at all in my setup.
Rotala ‘Blood red’ emersed vs submersed
The rotala arrived having been grown emersed in a rockwool pot, which is very common in the industry. The emersed form has smaller rounder thicker leaves. I was a little surprised after having prised away the rockwool prior to planting just how shallow the root system of the rotala was, but happily that does not seem to have been a problem. In the emersed form the stems are perhaps more red than the leaves. After two weeks of submersed growth the new leaves definitely have a red character to them, and they are longer, thinner and more narrow than the emersed form leaves.
Rotala ‘blood red’ in rockwool
Rotala ‘blood red’ new stems
Rotala ‘blood red’ after 2 weeks
Rotala colour is condition dependent
After 10 weeks in the Fireplace Aquarium the rotala is getting to a mature state. The leaves continue their narrow pointy characteristics. Instead of ‘blood red’ I might call the colour more of a ‘burnt ochre’ which is still a nice contrast with the green of the Anubias and the Bacopa.
Unsurprisingly, the colour of the Rotala is strongly dependent upon growth conditions. If you want it to look really spectacularly red it needs to (apparently) be grown under high light and with low nitrate levels. The lighting in the Fireplace Aquarium is not what I would describe as ‘high’ – the Kessil A80 LED has a max draw of 15W and I only run it at a max of 70% power (so just over 10 W) to limit growth of green spot algae. I don’t attempt at all to have “low nitrate” levels, in fact I deliberate add nitrate to 15 ppm as a component of the Estimative Index fertilisation program, and that is in addition to the baseline average 37 ppm nitrate in the Cambridgeshire tap water.
Rotala ‘blood red’ after 10 weeks
Rotala ‘blood red’ in higher light
Rotala (back left)
There is some word in the hobby that there is a specific subvariety of Rotala ‘Blood red’ called the Singapore variant or the ‘SG’ variant which is less sensitive to nitrate levels and gives a more consistent red colour. I suspect that is pretty much just 100% marketing – none of the major sites like Tropica, Dennerle or AquaFleur have this on offer. Nevertheless, I’ve just put a little money down on Ebay to source some so we’ll be able to do a compare and contrast in due course.