1/4 Cup of Water Spangles (Salvinia Minima)/Duckweed Mix varying sizes (may contain snails). Salvinia and Duckweed are low maintenance, floating plants that spread accross the top of an aquarium. It thrives in medium light and temps ranging from 64-84 F. Salvinia and Duckweed are great for reducing the amount of nitrates & nitrites in aquariums.