Plant Profiles

Isoetes coromandelina

Isoetes coromandelina
Coromandel Coast Quillwort
$64.95

Isoetes coromandelina, is an extremely rare aquatic plant, native to Australia, India and Southeast Asia. It is a unique and fascinating aquatic plant that belongs to the Isoetes genus, commonly referred to as the quillworts. This particular species was first discovered on the Coromandel Coast of India and is a very rare find in the aquarium hobby. It has a classic Isoetes appearance, with many long green leaves that grow out of a lobed corm. Isoetes are also sometimes refered to as octopus plants due to these numerous splayed leaves.

Isoetes coromandelina looks quite similar to some Eriocaulon species, like Eriocaulon breviscapum, but is far more foregiving in its requirements. Unlike Eriocaulon, Isoetes do not require soft water to thrive and are fairly easy to grow in most aquariums.

It is important to provide this species with a nutritious substrate, as Isoetes are very heavy root feeders. Quillworts are an ancient group of plants in the Lycophyte clade, which are related to ferns. Isoetes photosynthesise very differently to most other plants, and so do not require additional CO2 in the aquarium.

Quillworts utilise crassulacean acid metabolism (CAM) for carbon fixation, a process typically used by plants in arid environments to minimise water loss by opening their stomata at night. Aquatic quillwort species have very few stomata and have thick cuticles on their leaves, which limits CO2 uptake. Instead, they absorb CO2 from the sediment through their hollow roots. This strategy helps quillworts avoid competition for CO2 with other aquatic plants during the day. Once CO2 is absorbed through the roots, it travels through air canals in the leaves, facilitating gas diffusion to the photosynthetic tissue.

For this reason, it is very important to provide Isoetes with a good quality substrate. Dense substrates are preferred - either clay based, sand or fine gravel with dirt or peat. This plant is adaptable to a range of water parameters, but it generally prefers slightly acidic to neutral pH levels and moderate water hardness.

The Coromandel Coast Quillwort has a rosette-like growth form, with slender, cylindrical leaves. These leaves are typically lime green in color and can grow to varying lengths depending on the conditions, but usually get to a maximum length of 30cm. It is a fairly slow growing species that retains its leaves well, with mature plants having a dense rosette of many leaves.

Isoetes coromandelina requires moderate to high lighting to thrive and grow properly. Additionally, providing nutrients through root tabs or a nutrient-rich substrate can enhance its growth.

This quillwort species is best suited for a midground placement in the aquarium. Isoetes coromandelina is an attractive choice for aquarists looking for something different, with its quill-like leaves and adaptable nature.

Requirements and information

Temperature:
TropicalWarm   Cold

Substrate type:
Coarse   Fine

Substrate nutrients:

High

Water nutrients:

Medium

Light demand:

Medium

CO2:

Low

Height:

Tall

Growth rate:

Slow

Growth habit:

Rosette

Difficulty:

Intermediate

Native to: