Ketapang Leaves. An Alternative to Peat Based Blackwater Extracts Ketapang Leaf otherwise known as TERMINALIA CATAPPA (or commonly called Indian almond) releases organic acids like humic and tannins which lowers the pH of the water, absorbs harmful chemicals and help create a soothing and calm environment for the fish. It also has anti-bacterial properties. Breeders in Asia have used them as a conditioning agent for their aquarium fish, to spur breeding behaviour as well as an add-on for fishes packaged for shipment. Ketapang Leaf Extract contains the same benefits while eliminating the fuss of leaf collection and processing for you. All Ketapang leaves are cleaned and heat-treated to obtain the resulting concentrated extract. Use 2 to 3 drops per litre of water and for Betta Crowntails, it is recommended to increase this to 3 to 4 drops.