08/18/2026
New item!!
Crinum thaianum – Thai Onion Plant
Crinum thaianum, commonly known as the Thai Onion Plant, is a striking aquatic bulb plant native to Thailand. It develops long, bright green, ribbon-like leaves that can grow several feet in length, creating a beautiful flowing effect as they move with the current. Its unusual bulb-shaped base and impressive size make it an excellent centerpiece or background plant for larger planted aquariums.
Unlike many aquarium plants, Crinum thaianum is a true bulb plant and can become a substantial specimen with age. Once established, it is hardy, long-lived, and relatively easy to maintain. The long leaves can reach the water’s surface and trail across the aquarium, giving the tank a lush, natural appearance.
Care Instructions
Difficulty: Easy to Moderate
Lighting: Low to High; moderate lighting is ideal
CO₂: Not required, but beneficial
Growth Rate: Slow to Moderate
Placement: Background / Centerpiece
Temperature: 72–82°F
pH: 6.0–8.0
Water Hardness: Soft to Hard
Substrate: Nutrient-rich substrate recommended
Maximum Size: Leaves can reach 3–6+ feet long in ideal conditions
Planting
Plant the roots into the substrate while keeping most of the bulb exposed above the substrate. Do not completely bury the bulb, as this can encourage rot. A mature root system will eventually anchor the plant securely.
Crinum thaianum is a heavy root feeder, so root tabs are recommended when using an inert or nutrient-poor substrate.
Trimming & Maintenance
Because the leaves naturally grow extremely long, give this plant plenty of room. Older or damaged leaves can be removed by cutting them near the base. Avoid repeatedly cutting healthy leaves simply to keep the plant short; Crinum thaianum looks best when allowed to develop its characteristic long, flowing foliage.
Additional Notes
Crinum thaianum may take some time to establish after planting or shipping, so don’t be concerned if growth is initially slow. Once it develops a strong root system, it becomes an impressive and durable aquarium plant.
Important: This is a large aquarium plant. It is best suited for medium-to-large aquariums where its long leaves have room to grow and flow naturally.