Crinum thaianum is an excellent plant for the aquarium. Crinum thaianum, more commonly know as onion plant, grows in rivers and streams in Southeast Asia. The large bulb on Crinum thaianum helps it to store energy through the dry spells. Crinum thaianum is best used in the mid or background areas of the aquarium. Large white flowers adorn Crinum thaianum when it is low water or emmersed. Crinum thaianum is a great aquarium plant for beginners because of its ability to live in a variety of different conditions.