Lysimachia nummularia, commonly known as Creeping Jenny, is a fast-growing, low-maintenance aquatic plant that adds a pop of vibrant green to your aquarium. Known for its small, round, and bright green leaves, Creeping Jenny is a versatile and hardy plant that works beautifully in both submerged and emergent environments. Native to Europe and parts of Asia, Creeping Jenny is ideal for adding texture to aquascapes, creating a lush ground cover, or as a trailing plant in paludariums and ripariums.

In the aquarium, Lysimachia nummularia can be used as a foreground plant or along the substrate as a carpet. It is also popular in aquariums with aquascaping setups that require fast-growing plants to cover large areas quickly. Creeping Jenny is especially valued for its adaptability and ability to thrive in a wide range of water conditions, making it an excellent choice for both beginner and advanced aquarists.

Key Features:

- Compact, Round Leaves: Creeping Jenny features small, round, and bright green leaves that grow densely along the stem, creating a soft, bushy appearance. The plant’s leaves can form a lush, carpet-like mat when placed in the foreground.
- Fast-Growing & Groundcover: Lysimachia nummularia is a fast-growing plant that quickly spreads to form a dense carpet, ideal for filling in gaps or covering substrates in a short period.
- Adaptable to Varied Conditions: Creeping Jenny is highly adaptable and can grow in a variety of light conditions (low to moderate), temperatures, and water parameters, making it a versatile choice for many aquarium setups.
- Ideal for Foreground and Carpet: Its low-growing habit makes Creeping Jenny perfect for carpeting the foreground of your aquarium. It can also be used as a trailing or cascading plant in aquascaping designs, adding a lush, green dimension to the overall layout.
- Versatile Placement: Creeping Jenny can be grown fully submerged in an aquarium or partially submerged in a riparium or paludarium. It also thrives in wetland environments and works well in aquaponic and pond systems.

Benefits:

- Fast Ground Cover: Lysimachia nummularia spreads quickly, making it an excellent option for aquascapers looking to create ground cover in a short amount of time. It helps fill empty spaces and adds texture to the aquarium layout.
- Natural Algae Control: Like many aquatic plants, Creeping Jenny absorbs excess nutrients from the water, including nitrates, phosphates, and trace minerals, which helps reduce algae growth and maintain a healthier, more balanced aquarium environment.
- Oxygenation & Water Quality: As a vigorous photosynthetic plant, Creeping Jenny contributes to the oxygenation of the water, especially in densely planted tanks. It helps improve water quality by absorbing pollutants and creating a more balanced ecosystem.
- Provides Shelter: The dense growth of Creeping Jenny provides hiding spots for small fish, shrimp, and invertebrates. It offers a natural environment for breeding, giving shelter to fry and baby shrimp.
- Aesthetic Appeal: Creeping Jenny brings a natural, lush look to aquascapes, making it a great choice for enhancing the beauty of the tank. Its bright green foliage complements other plants and creates a visually appealing contrast in aquascaping.

Care Instructions:

- Lighting: Creeping Jenny does well in low to moderate light, although higher light levels will encourage denser, more compact growth. In low light, it may grow slower and become leggier. For optimal results, aim for medium lighting (2-3 watts per gallon).
- Water Conditions: Lysimachia nummularia prefers slightly acidic to neutral water (pH 6.0–7.5) and a temperature range of 68°F to 80°F (20°C–27°C). It can tolerate both soft and moderately hard water but thrives best in nutrient-rich water.
- Substrate & Planting: Creeping Jenny can be planted in the substrate or attached to rocks or driftwood if you wish to create a trailing or cascading effect. It does not require deep planting; simply press the stems lightly into the substrate to encourage rooting. The plant can spread rapidly by sending out runners, so it can quickly cover large areas of the substrate.
- CO2 & Fertilization: While Creeping Jenny does not require CO2 injection to thrive, providing it with CO2 supplementation in high-light setups will promote faster growth. Liquid fertilizers can be used to supplement nutrients, especially in nutrient-poor substrates or water.
- Maintenance & Pruning: Regular trimming may be necessary to maintain Creeping Jenny’s shape and prevent it from overtaking other plants in the aquarium. Removing any dead or decaying leaves helps encourage healthy growth and maintains its appearance. Prune excess growth as needed to keep it in check.

Applications:

- Freshwater aquariums (foreground or carpet plant)
- Paludariums or ripariums (partially submerged)
- Pond aquariums or water gardens
- Aquascaping projects where ground cover is needed
- Aquariums with shrimp or breeding fish (providing shelter)

Note: Creeping Jenny can grow quickly under the right conditions and may require regular thinning to prevent it from overcrowding other plants. While it can grow in low-light environments, it will thrive and appear more compact and vibrant with moderate to high lighting. 

Lysimachia nummularia (Creeping Jenny) is a highly adaptable, fast-growing plant that brings lush greenery and texture to any aquarium. Whether used as a ground cover, a foreground carpet, or a cascading plant in paludariums, Creeping Jenny is an excellent choice for aquascaping enthusiasts of all levels. Its quick growth, ease of care, and ability to improve water quality make it a valuable addition to any freshwater setup. With proper care, Creeping Jenny will thrive and provide a beautiful, natural aesthetic for your aquarium.