*Pellia moss*, also known as *Pellia*, is a popular aquatic moss species in the hobbyist aquarium trade. It is known for its dense, carpet-like growth and its ability to thrive in a variety of aquarium conditions. Here are some key points about Pellia moss:

1. Appearance: Pellia moss forms dense, dark green mats of small, leaf-like structures. It has a unique appearance that can resemble liverwort plants and can create a lush, carpeting effect in aquariums.

2. Lighting: Pellia moss can grow under a wide range of lighting conditions, from low to high light. However, it tends to grow more slowly under lower light levels and may become leggy if light is insufficient.

3. Water Conditions: It prefers slightly acidic to neutral pH levels (around 6.0-7.5) and temperatures between 64-82°F (18-28°C). Good water circulation helps to prevent algae growth and maintain the health of the moss.

4. Substrate: Pellia moss can be attached to various surfaces in the aquarium, such as rocks, driftwood, or substrate. It does not require a nutrient-rich substrate but benefits from occasional supplementation with liquid fertilizers.

5. CO₂ and Nutrients: While CO₂ injection is not necessary for Pellia moss, providing CO₂ supplementation can enhance its growth and promote denser, healthier mats. Regular fertilization with micronutrients helps to maintain its vibrant green coloration.

6. Propagation: Pellia moss propagates through fragmentation. Small pieces of the moss can be attached to surfaces using thread or glue, and they will eventually grow and spread to form new mats.

7. Placement: Pellia moss is versatile and can be used in various ways in the aquarium. It can be attached to hardscape elements like rocks and driftwood to create natural-looking scapes or used as a foreground or midground carpeting plant.

8. Compatibility: Pellia moss is compatible with most freshwater fish and invertebrates. It provides cover and shelter for aquarium inhabitants and helps to create a natural and aesthetically pleasing environment.

9. Maintenance: Regular maintenance includes trimming to control its growth and shape. Removing debris and dead moss helps to maintain water quality and prevent algae buildup.

Pellia moss is valued by aquarists for its ease of care and ability to enhance the visual appeal of aquariums. If you have more specific questions or need further information about Pellia moss, feel free to ask!