Comparison of Dwarf Water Hyssop (Bacopa monnieri) in Emerged and Submerged Systems in Aquariums

Abstract

Dwarf water hyssop (Bacopa monnieri) is a popular choice among aquarium enthusiasts for its ease of care and rapid growth. Despite its popularity, research on its suitability as an aquarium plant is scarce. The objective of this study was to assess the effects of various fertilizer formulas and growth performance in both emerged and submerged culture systems. Dwarf water hyssop was cultured for four weeks in emerged and submerged systems using different NPK fertilizer formulas (18-18-18, 25-5-5, 30-20-10, and 8-24-24), alongside a control group without fertilizer. Remarkably, growth performance (i.e. plant height, number of leaves, number of nodes, and root length) and survival rate did not significantly differ between plants with and without fertilizer application in either culture system. Among the fertilizers tested, treatment 4 (NPK 30-20-10) showed the most promising results for dwarf water hyssop growth in both emerged and submerged culture systems. In the emerged system, these treatments led to a minimum height increase (7.96±1.49 cm), a medium number of new leaves (4.41±1.91 leaves/explant), a moderate number of new nodes (3.08±0.29 nodes/explant), and a substantial root system length (2.67±1.16 cm). Conversely, in the submerged system, a minimum height increase (1.65±0.32 cm), medium number of new leaves (1.33±1.66 leaves/explant), moderate number of new nodes (1.08±0.76 nodes/explant), and root system length (0.36±0.86 cm) were observed. Overall, plant morphology and growth performance were superior in the emerged system compared to the submerged system after four weeks of culture. Outstandingly, all plants survived, regardless of fertilizer application of formula, in both culture systems. Given its slow growth, dwarf water hyssop is ideal for aquarists seeking a dwarf aquatic decoration. The emerged culture system is recommended for mass production of this ornamental plant, while the submerged culture system is suitable for elaborate ornamental aquariums.