Najas guadaloupensis

Scientific name: Najas guadaloupensis

Family: Najadaceae

Maximum size reached under cultivation: 50 - 100 cm (19.69 - 39.37 inch)

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Recommended pH range: 6 - 7

Recommended water hardness: 2 - 10°dGH (35.71 - 178.57ppm)

0°C 32°F30°C 86°F

Recommended temperature range: 23 - 26 °C (73.4 - 78.8°F)

Preferred propagation method: Cuttings

Native to: North America

Growth rate: Fast

Recommended substrate: Fine gravel

Lighting requirements: Medium

Ideal placement in tank: Background

Family

Najadaceae

Common Name

Guppy Grass

Propagation

Najas guadaloupensis reproduces easily through stem cuttings. Any healthy portion of the plant can be trimmed and replanted directly into the substrate or left to float freely. Due to its fragile and delicate stems, it's best to handle with care when trimming or relocating. Planting cuttings in small groups can provide mutual support and encourage vertical growth. It thrives in calm water with low to moderate flow, and even the smallest fragments can root and regenerate quickly under proper lighting.

Difficulty

Easy. This species is undemanding and well-suited for beginners. It adapts quickly to various conditions and grows rapidly with minimal maintenance, making it ideal for breeding tanks or nature-style layouts.

Short Description

Native to North America, Najas guadaloupensis, commonly known as Guppy Grass, is a fast-growing aquatic plant that can be planted or floated in freshwater aquariums. It typically reaches lengths of 50 to 100 cm (19.69 – 39.37 inches), forming soft, feathery green foliage that provides excellent shelter for fry, shrimp, and small fish. The plant can be anchored in fine gravel substrate, but also thrives when left to float, especially in breeding or shrimp tanks. Its quick growth helps absorb excess nutrients, contributing to algae control and overall water quality.

Although it is rarely seen in aquarium shops, it is highly valued by aquarists who want a natural and low-maintenance background or floating plant. The species is adaptable and performs well in a wide range of tropical freshwater environments. Other species of Najas occasionally found in aquariums include Najas indica and Najas conferta.

Maintenance and Care

Najas guadaloupensis grows best at temperatures between 23 – 26°C (73.4 – 78.8°F), with a pH range of 6.0 to 7.0 and water hardness from 2 – 10°N (35.71 – 178.57 ppm). Medium lighting is sufficient for healthy growth, though increased light can accelerate growth even more. It does not require CO₂ injection or special fertilizers, but benefits from balanced nutrients in the water column. As a fast grower, regular trimming is necessary to prevent overgrowth and to maintain open swimming areas.

Compatibility

This plant is highly compatible with peaceful fish, shrimp, and fry. It provides excellent protection for young or timid fish and enhances biological filtration by absorbing excess nutrients. Avoid keeping it with rough herbivorous fish that may damage its fine leaves. Due to its fragility, it’s best suited for community tanks with low to moderate water flow.

Submersion and Aquascaping

Najas guadaloupensis is a fully aquatic, submerged plant. It does not grow emersed and is therefore not suitable for paludariums. In aquascaping, it can be used as a background plant to add vertical texture or floated freely to create shaded areas. Its thin, bright green leaves offer a natural look and dynamic movement in the water. While not a classic aquascaping showpiece, it plays a vital role in natural-style and functional setups.