Eriocaulon ratnagiricum is an endangered species that originates from India. It has been in the aquarium trade among hobbyists for sometime although it has not been commercially propagated at scale. Its distinctive spiky look differentiates it from other species of plants. Eriocaulon ratnagiricum is one of the smallest Eriocaulons, with an adult size of around 2.5 inches. It also flowers less often underwater compared other Eriocaulons such as E. polaris or E. cinereum. This allows it to grow in its pleasing porcupine form for long term.
It has the reputation of being hard to grow; however, upon understanding its requirements it is actually reasonably easy to grow and propagate. It grows quickly, with good resilience as long as its growth conditions are fulfilled.
This plant grows very well in ammonia rich aquasoils, and the usage of rich, acidic substrates accelerate growth significantly. It grows better with higher light and CO2 levels compared to easier aquarium plants. As a short plant - it's important to direct flow/CO2 to the substrate zone and make sure it is not shaded by taller plants. It is sensitive to KH and should be kept in low alkalinity water (<3dKH). This means that it is not suitable for tanks with Seiryu rocks.
It has a large root system despite a rather short crown. Substrate should not be too thin (< 2inches) if you want to grow them to good size.
Flower stalks should be removed if they appear; if not, the plant may channel most of its energy into growing flower stalks instead of vegetative growth.
Small plantlets beside some young Eriocaulon ratnagiricum. These are planted far too close for each to grow to full adult size; this is alright if the intention was to uproot them before they are fully grown (to sell or to propagate further).
The plant sometimes produces baby plants naturally as it grows larger. However, in stable tanks the plant often does not divide frequently, and just grows larger with time. Sometimes uprooting/replanting or damaging the plant can cause plantlets to be formed, however, the better method is to split the Eriocaulon in an even half manually - both parts will grow into separate plants.
Eriocaulon ratnagiricum tend to spawn many baby plantlets from each half when divided into half. This will give rise to a cluster of smaller plantlets around each crown. If left to its own devices, the plantlets may suffer from over-crowding - the cluster should be uprooted again, and the plantlets separated and planted individually. Each plantlet will tend grow to a full sized plant in time.
You can read more on propagating Eriocaulons on this page