Cardamine lyrata, commonly known as Japanese Buttercup or Lyrate Cardamine, is a versatile and attractive aquatic plant often used in freshwater aquariums and aquascaping. It belongs to the family Brassicaceae, and it is native to East Asia, specifically Japan, China, and Korea. This plant is appreciated for its delicate, feathery appearance and its ability to thrive in a variety of aquarium setups.

Here’s a detailed description of Cardamine lyrata:

1. Appearance:

• Leaves: The most distinctive feature of Cardamine lyrata is its finely divided, fern-like leaves. The leaves are lyrate (resembling the shape of a lyre or harp), with a deeply lobed structure that creates a delicate, feathery look. They are a vibrant green in color and grow in a rosette pattern near the base of the plant.
• Stems: The plant’s stems are typically slender and may appear light brown or reddish. The stems grow upwards from the rosette and can reach heights of 8–16 inches (20–40 cm) in an aquarium setting.
• Growth Pattern: Cardamine lyrata grows in a compact, bushy form, making it an excellent choice for the midground or foreground of an aquarium. When left to grow freely, it can develop a more dense, bush-like appearance.

2. Care Requirements:

• Light: This plant thrives under moderate to high lighting. In low-light conditions, its growth may slow down, and the plant may become leggy with less vibrant foliage.
• Water Conditions: Cardamine lyrata prefers temperatures in the range of 68–82°F (20–28°C) and does well in soft to moderately hard water. The pH should be slightly acidic to neutral (6.0–7.5), and it can tolerate a variety of water hardness levels.
• Substrate: It grows best in a nutrient-rich substrate, but it can also tolerate gravel or sand. Adding root tabs or a source of liquid fertilization will help support its growth.
• Nutrients: Regular fertilization is beneficial for promoting healthy growth. Providing adequate levels of CO₂ will also encourage strong, vibrant growth.

3. Propagation:

• Division: Cardamine lyrata can be propagated by dividing its rosettes or by cutting and replanting healthy stems. The plant will produce new growth from the nodes, which will grow into new plants.
• Offsets: It can also propagate through offsets, where new plants form at the base of the original plant. These can be separated and replanted.

4. Aquarium Use:

• Aesthetic Appeal: Due to its finely divided, feathery leaves and compact growth, Cardamine lyrata adds a lush, soft texture to aquascapes. It can be used in midground or foreground placements, where it will not overwhelm other plants but will still stand out with its unique foliage.
• Growth Behavior: This plant grows relatively quickly under ideal conditions. It is a great addition to aquascapes seeking plants that can fill in spaces or provide textural contrast against plants with broader, more solid leaves.

5. Compatibility:

• Fish: Cardamine lyrata is generally safe for all types of aquarium fish. Its delicate leaves are not typically attractive to fish, and it’s unlikely to be damaged by their activity. However, herbivorous or algae-eating species might occasionally nibble on it.
• Shrimp and Snails: It is safe for shrimp and snails, and can even offer them additional shelter or grazing opportunities, although larger snails may occasionally damage the plant.

6. General Considerations:

• Moderate Maintenance: Cardamine lyrata is relatively easy to care for, though it does benefit from proper lighting and nutrients to reach its full potential. It is not highly demanding compared to other aquarium plants, making it a good choice for both beginners and experienced aquarists.
• Versatility: This plant works well in a wide range of setups, from low-tech tanks to high-tech, CO₂-injected aquariums. It also does well in aquariums with moderate fish populations, and it is a great choice for aquascapes that require fine-leafed plants.

Conclusion:

Cardamine lyrata is a charming and adaptable plant that brings a light, airy feel to any aquarium. Its feathery, finely divided leaves, compact growth, and ease of care make it a popular choice in aquascaping. Whether used in the foreground or midground, it’s an excellent plant for adding texture and contrast in any aquatic setup.