*Hydrocotyle leucocephala*, commonly known as Brazilian pennywort, is a versatile and attractive aquarium plant known for its fast growth and ease of care. It can be used both as a floating plant and as a rooted plant in the substrate, making it suitable for a variety of aquascaping styles.

Here are some key points about *Hydrocotyle leucocephala*:

1. Appearance: *Hydrocotyle leucocephala* has round, bright green leaves that resemble miniature lily pads. The leaves are attached to thin, flexible stems that can grow quickly and reach the surface of the water.

2. Lighting: This plant thrives under moderate to high lighting conditions. Adequate lighting will promote rapid growth and keep the leaves vibrant and healthy. Under low light, growth may slow down, and the plant may become leggy.

3. Water Conditions: *Hydrocotyle leucocephala* is adaptable to a wide range of water conditions, preferring slightly acidic to neutral pH levels (6.0-7.5) and temperatures between 68-82°F (20-28°C).

4. Substrate: While *Hydrocotyle leucocephala* can grow well in various substrates, it benefits from a nutrient-rich substrate if planted. It can also grow as a floating plant, where it will absorb nutrients directly from the water column.

5. CO₂ and Nutrients: Although not strictly necessary, providing CO₂ supplementation can enhance the growth and overall health of *Hydrocotyle leucocephala*. Regular fertilization with a comprehensive liquid fertilizer is recommended to support its nutrient needs.

6. Propagation: This plant propagates easily through cuttings. Simply cut a section of the stem with leaves and plant it in the substrate or let it float. The cuttings will quickly develop roots and grow into new plants.

7. Placement: *Hydrocotyle leucocephala* is versatile in its placement. It can be used as a background or midground plant when rooted in the substrate, or as a floating plant to provide cover and shade. Its trailing stems can also create a cascading effect in the aquarium.

8. Care Level: *Hydrocotyle leucocephala* is considered easy to care for, making it a suitable choice for beginners. Its fast growth helps it outcompete algae and contribute to a balanced aquarium ecosystem.

9. Compatibility: This plant is compatible with most freshwater fish and invertebrates. Its dense foliage provides hiding spots and can help reduce stress for tank inhabitants.

10. Maintenance: Regular trimming is necessary to control the growth and shape of *Hydrocotyle leucocephala*. Pruning helps to maintain its compact form and prevents it from overtaking other plants in the aquarium.

If you have any more specific questions or need additional details about *Hydrocotyle leucocephala*, feel free to ask!