Great for Bubble Nests and Spawning Provides Hiding Spaces for Fry Naturally Adds Tannins and Humic Acid Anti-Fungal and Anti-Bacterial Properties Great for Freshwater Shrimp Ideal for Betta and Biotope Systems Fritz Nature Box contains Indian Almond leaves, sliced Catappa almond bark, and Casuarina cones, each giving a unique application of tannins, humic acid, and habitat. Each provides tannins, lowers pH, has anti-fungal and anti-bacterial properties, enhances coloration and increases spawning behavior. The tannins released from these pieces create a more natural environment for Bettas, shrimp and other fish. Almond leaves, almond bark, and Casuraina cones contain humic acids and tannins which are known to have antibacterial properties, naturally lower pH and create blackwater conditions in the aquarium. Fritz Nature Box is suitable for all soft-water fish including betta, discus, tetras, angelfish, and killifish.