• Scientific name: Najas guadalupensis
• Synonym: Caulinia guadalupensis, Najas microdon
• Common name: Common waternymph, Southern waternymph, Guppy grass
• Family: Najadaceae
• Group: Aquarium plants
• Max height: 70 cm
• Distribution: North, Central and South America
• Habitat: Inhabits both stagnant water, such as marshes and lakes, as well as streams and rivers featuring slow currents.
• Substrate: Washed gravel
• Placement in aquarium: Middleground
• Lighting needs: Medium bright
• Temperature: 20-30°C
• pH: 6-7
• Hardness: 2,8-10NK°

Description: Najas guadalupensis is an expressedly undemanding and rapid-growing plant, which will produce densely intertwined populations within only a short time making it especially useful in breeding aquariums. The shoots have the negative characteristic of breaking off easily at the nodes and then drifting on the water surface as fragments in large numbers where they continue to develop; probably for this reason the plants are not suitable for commercial sale. But because the species is undemanding as to substrate, ligh or water condition, it has nevertheless occasionally been cultivated for many years.