It is a very beautiful aquatic plant that is a fairly popular choice for aquariums, both because it looks nice and because it is not too difficult to grow, that being said it does require some specific conditions and a fair amount of care to grow successfully.
The Crinum Natans is a plant with a thick base and long thin leaves. The leaves will be bright green and darker green in color, they grow to over one foot long and as tall as 5 feet long, and they are elongated and ruffled. These features make this plant very nice for aquariums because they add some great color and the leaves move around in the water with an elegant flow.
Seeing as it is a very large plant you will need a very big aquarium in terms of space requirements, that or you need to prune it often to keep it small. That being said this plant does have a fairly slow growth rate so it will take some time until it reaches its full size.
In terms of what this plant needs to grow, it needs a fair amount of lighting, that being about 5 watts per gallon of water. Not having enough light will retard the growth of the plant and may make it turn yellow, wither, and maybe even die completely. This plant also requires a fair amount of fertilization and nutrients such as phosphate and iron in order to thrive.
This plant also needs good CO2 supplementation (more on that here) in the water to survive. Without the required nutrients and CO2 this plant will not do very well. The substrate that the Natans is planted in also needs to be quite rich in nutrients. The water for this plant needs to be fairly warm, between 20 and 28 degrees Celsius. Also, the water needs to have a pH level in between 5.0 and 7.0. In terms of temperature and the pH level this plant can handle quite a bit so that shouldn't be a big problem.
If you want to grow more of the Crinum Natans plant then all you need to do is take the bulb offshoots and plant them in dirt. These offshoot bulbs cannot be grown immersed in water and need to be grown on dry land. On a side note, if this plant is healthy it will send a shoot to the water’s surface and actually create a flower. These plants are quite versatile, aren't too hard to grow, and make a beautiful addition to any aquarium.