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Crinum thaianum

Thai onion plant — long wavy leaves for the background

Regular price
£15.99
Regular price
Sale price
£15.99
  • Hurry, only 2 items left in stock!
Quick Facts

Common name: Onion Plant

Origin: Africa

Position in Aquarium: Background

Grows up to (cm): 100 cm

Pot Size: 5 cm

Growth rate: Medium pace

Description

Crinum thaianum — commonly known as the Onion Plant — produces very long, strap-like, wavy leaves that make it one of the most distinctive background plants for larger aquariums. The leaves can grow well beyond 1m in good conditions, making it ideal for concealing equipment such as heaters and filters behind lush trailing foliage.

A useful characteristic: fish that typically graze on aquarium plants tend to leave Crinum thaianum entirely alone — apparently deterred by its flavour. This makes it a reliable choice for tanks with herbivorous fish where other plants struggle to survive. Care requirements are simple: low light, no CO2, and only the lower third of the bulb buried in the substrate. Bury it more deeply and the bulb will rot.

Note: the specimens we receive rarely have as many leaves as shown in the product image — the picture shows a mature specimen at its best. Individual plants vary naturally.

Plant Sizes

You’ll receive a healthy, rooted plant in a pot, similar to those shown. Each one is hand-checked before dispatch.

Shipping

Same-day dispatch on orders placed before 4pm, Monday to Friday. Tracked 24 Service from £4.99, DPD Express from £6.99.

Crinum thaianum (Water onion) Tropica
Crinum thaianum (Water onion) Tropica
Crinum thaianum (Water onion) Tropica

Customers praised this aquatic plant for its fast growth and excellent quality. Reviews highlight "good size and condition" upon arrival with healthy root systems. One customer noted it grew "almost to the top of 29" deep tank in just over a week." Plants arrive quickly and undamaged. All customers highly satisfied.

  • Fast growing plant, almost to top of 29" tank in just over a week.
  • Received onion plants quickly and undamaged. Root system was great quality.
  • Great product would buy again
  • 5 stars: 5 (100%)
  • 4 stars: 0 (0%)
  • 3 stars: 0 (0%)
  • 2 stars: 0 (0%)
  • 1 star: 0 (0%)
E
Etsy c.

Great product would buy again

R
Richard

Good size and condition

T
Terry B.
Review

Ordered for the first time and received onion plants quickly and undamaged. The roots system was a great quality and will be ordering more products in the future.

S
Steven H.
Review

This is definitely a fast growing plant , almost to the top of 29" deep tank in just over a week.

V
Victoria M.
Review

Plant arrived quickly, in good condition and good size. Very happy with item

Product FAQs

Helpful details before you buy.

Why is it called the Onion Plant?

The bulb resembles a large onion. It's planted in the substrate, from which the long strap-like leaves emerge.

Will fish eat it?

No — fish almost universally avoid Crinum thaianum, apparently because of its taste. Popular in tanks with herbivorous fish for this very reason.

How deep should I plant the bulb?

Only the lower third of the bulb should be in the substrate — no more. Burying it deeper causes rot.

How long do the leaves get?

Well over 1m in good conditions — primarily a plant for larger aquariums where leaf length won't be a problem.

Does it need CO2?

No — it's suitable for low-tech setups without CO2 supplementation.

Skip to product information
1 of 4

Crinum thaianum

Thai onion plant — long wavy leaves for the background

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Easy care Low light CO2 not required Background plant
Regular price
£15.99
Regular price
Sale price
£15.99
  • In stock — 2 available

In-stock orders normally dispatch before 4pm, Monday–Friday. Delivery details

Crinum thaianum (Water onion) Tropica
Crinum thaianum (Water onion) Tropica
Crinum thaianum (Water onion) Tropica

Complete your setup

Useful additions for your aquarium

Care essentials chosen for this plant

Healthier plants
Brighter results
Neutro T Aquarium Plant Fertiliser Recommended size
£10.99
Root nutrition Neutro TerraTabs - Root Tabs for Planted Aquariums

Long-lasting nutrition
for strong, healthy roots.

Recommended size
£9.99
Superfish Aquarium Plant Tweezers Recommended size
£4.99
Useful additions for planting day Carefully packed with your plants Specialist aquarium plant care
Bundle offers

About this plant

Crinum thaianum — commonly known as the Onion Plant — produces very long, strap-like, wavy leaves that make it one of the most distinctive background plants for larger aquariums. The leaves can grow well beyond 1m in good conditions, making it ideal for concealing equipment such as heaters and filters behind lush trailing foliage.

A useful characteristic: fish that typically graze on aquarium plants tend to leave Crinum thaianum entirely alone — apparently deterred by its flavour. This makes it a reliable choice for tanks with herbivorous fish where other plants struggle to survive. Care requirements are simple: low light, no CO2, and only the lower third of the bulb buried in the substrate. Bury it more deeply and the bulb will rot.

Note: the specimens we receive rarely have as many leaves as shown in the product image — the picture shows a mature specimen at its best. Individual plants vary naturally.

Preparing a potted plant

Gently remove the pot and growing wool, then follow the planting advice for this species.

Potted plant care guide
Delivery & live plant guarantee

Orders placed before 4pm Monday–Friday normally dispatch the same working day. Special-order items leave once all items are available.

Delivery options and charges · Returns and guarantees · Help with plants that arrived damaged

Customers praised this aquatic plant for its fast growth and excellent quality. Reviews highlight "good size and condition" upon arrival with healthy root systems. One customer noted it grew "almost to the top of 29" deep tank in just over a week." Plants arrive quickly and undamaged. All customers highly satisfied.

  • Fast growing plant, almost to top of 29" tank in just over a week.
  • Received onion plants quickly and undamaged. Root system was great quality.
  • Great product would buy again
  • 5 stars: 5 (100%)
  • 4 stars: 0 (0%)
  • 3 stars: 0 (0%)
  • 2 stars: 0 (0%)
  • 1 star: 0 (0%)
E
Etsy c.

Great product would buy again

R
Richard

Good size and condition

T
Terry B.
Review

Ordered for the first time and received onion plants quickly and undamaged. The roots system was a great quality and will be ordering more products in the future.

S
Steven H.
Review

This is definitely a fast growing plant , almost to the top of 29" deep tank in just over a week.

V
Victoria M.
Review

Plant arrived quickly, in good condition and good size. Very happy with item

Product FAQs

Why is it called the Onion Plant?

The bulb resembles a large onion. It's planted in the substrate, from which the long strap-like leaves emerge.

Will fish eat it?

No — fish almost universally avoid Crinum thaianum, apparently because of its taste. Popular in tanks with herbivorous fish for this very reason.

How deep should I plant the bulb?

Only the lower third of the bulb should be in the substrate — no more. Burying it deeper causes rot.

How long do the leaves get?

Well over 1m in good conditions — primarily a plant for larger aquariums where leaf length won't be a problem.

Does it need CO2?

No — it's suitable for low-tech setups without CO2 supplementation.