How to grow Rotala tulunadensis

Rotala tulunadensis is a recent addition to the hobby. It is a delicate stem plant with unique oval-shaped leaves green leaves. In higher light levels, the leaves are very densely stacked onto the stem and get a slight reddish hue. It branches readily to form dense bushes even without much active trimming. Its light green leaves serves as a good contrast against darker greens and other colorful plants. It grows tall with time, hitting the top of most home aquariums. However, the plant has a moderate growth speed and can be easily trimmed back to maintain its height.

Rotala tulunadensis is a sensitive plant and many inexperienced aquarists have trouble growing it well long term. It prefers growing in soft water and though it is super particularly demanding in terms of light and CO2 and the failure to grow it has many aquarists puzzled. It has two main requirements:

Stable growth parameters

While Rotala tulunadensis does not require high amounts of light or CO2 to grow well, it does require very regular and consistent levels to grow well. This means that whether you dose heavily or lightly, the nutrient levels in the water column should be kept consistent. This is best demonstrated by the examples below:

Example 1.

Tank starts at 0ppm NO3. Daily dose of 1ppm NO3. Plant uptake rate of tank is 1ppm NO3. Tank measures consistently 0ppm NO3 residual levels in the water column. This is an example of lean dosing, leading to consistent residual levels (zero or near zero residual water column NO3).  

Example 2.

Tank starts at 15ppm of NO3 in the water column. Daily dose of 3ppm of NO3. Plant uptake rate of tank is 3ppm of NO3 a day. Tank measures consistently 15ppm of NO3 in the water column. This is an example of dosing more heavily, and water column nutrients are high, but the nutrient levels stay consistent across time. 

Example 3.

Tank starts at 0ppm NO3. Daily dose of 4ppm NO3 a day. Plant uptake rate of tank is 1ppm of NO3 a day. This causes a net daily accumulation of 3ppm a day. Tank starts at 0ppm of residual NO3 a day, rising to 15ppm of residual NO3 after 5 days. This is an example of heavy dosing, but inconsistent residual nutrient levels. Rotala tulunadensis will likely face problems in this tank. 

There is one approach that is easy to execute, while maintaining consistent water column levels: using a rich substrate while aiming to have low residual nutrient levels in the water column through dosing more on lean side. This has given rise to the observation that Rotala tulunadensis seems to be easier to grow in rich aquasoil substrates. However, the mechanism on which this works is that it is easier to have low stable water column nutrient levels when the plants can feed from a rich substrate to compensate for lower, stable nutrient levels in the water column. It can grow well at higher water column nutrient levels as long as they are kept consistent - keeping it consistent is the difficult part.

For folks that are used to maintaining higher residual water column nutrient levels, taking measurements periodically to stay within a consistent range will give better success with this plant.

This batch of Rotala tulunadensis is grown using APT Ei in the water column, and APT Feast substrate. Water column NO3 levels measure between 8-12ppm. Other water parameters: 5 dGH, 0.5 dKH.

Clean substrate/soil

The concept of clean soil is a tough one to understand. High levels of organic waste and decaying materials in the substrate can interfere with the root system of sensitive plants as they make the soil overly labile. If planted in aquasoil, the aquasoil should be vacuumed lightly to remove excess detritus and organic elements before planting. This can be done by agitating the top inch or so of the aquasoil with a turkey baster to stir up detritus while siphoning with the water change hose.

Grown using APT 3, APT Feast. Water column NO3 levels measure 0ppm consistently. Other water parameters: 5 dGH, 0.5 dKH.

Key success factors:

• Stable nutrient parameters in water column
• Soft water (less than 3 dKH of alkalinity)
• Clean substrate (see above)

Trimming and propagation

Rotala tulunadensis takes trimming well and branches readily from rooted portions. Keeping trimming off the tallest shoots and allow the plant to branch from lower portions and an attractive bush will be formed in time. 

For specimens that are mainly root fed, replanting tops can see short term stunting during replanting until roots are established again.