Are Indian Almond Leaves Good for Aquarium Fish?
Have you ever seen a stack of large, dried leaves at the fish store and wondered what they are for? Indian almond leaves (IAL) or catappa leaves come from Terminalia catappa, a tree that originates from Asia and Oceania but now grows in tropical and subtropical regions all over the world. Its fruit seeds taste similar to almonds, and its leaves are commonly used in herbal teas and traditional medicines.
The Indian almond tree bears fruit and leaves
Dropping a dried catappa leaves into aquarium water will cause it to slow decompose, producing tannins. These are plant-based compounds which gradually lower pH levels and leave the water stained yellow-brown. People don’t like the brownish tint that tannins naturally produce from leaves and driftwood. They can use chemical filtering to remove them.
What uses are Catappa leaves used for?
If you are a sensitive species (like crystal shrimps and certain South American fish), that may be a preference.
low pH and soft water
Indian almond leaves slowly lower pH levels by releasing tannic, humic, and fulvic acid organic compounds. They take longer to work than pH buffer chemicals, but their gradual effect is sometimes considered “safer” because they are less likely to cause deadly pH swings. The leaves have a negative impact on water chemistry and are not recommended for use by high-pH fish such as African cichlids or many livebearers.
While some soft water fish don’t require low pH for their normal living conditions, you may be more successful with breeding and raising their fry if you make the water more acidic. This is why breeders frequently use catappa leaves together with Apistogramma piscichilds or betta fish (both wild type and Betta splendens). For additional support, gouramis and betta fish sometimes make bubble nests under the leaves, as they float for the first few day.
Betta Fish in an Aquarium with Tan-Tinted Water
Interestingly, Indian almond leaves are known to have very slight antibacterial and antifungal properties. Tannins are found in nature to help plants resist the attacks of bacteria, fungus and other pathogens. Scientists continue to study their potential use in medicine. Aquarists love to use catappa plants to help their fish heal minor ailments and improve their immune systems. If your betta fish bites his tail constantly, tannins can help speed up his recovery. Some veterans also recommend adding tannin-rich leaves or alder cones when hatching fish eggs to fight off fungal growth.
Microorganisms consume the Indian almond leaves as they soak in water. They quickly reproduce and form a layer of infusoria. This microfauna can be a great food source for tiny shrimp and fry. It is often the only food that is small enough to be eaten by them in their first stages of life. If you’re planning on leaving town but don’t know anyone who can feed your shrimp colony, soak several leaves in water for three weeks. They will then become slimy and biofilmy. You can then drop them into your aquarium to make a long-lasting vacation food.
Blackwater biotope aquarium that imitates a Brazilian forest stream
You can also use lots of catappa and other botanicals to cover your ground if you’re trying to create a South American Biotype or a blackwater aquarium. Darker water allows shiny fish such as neon tetras and cardinal tetras to really shine. It also helps skittish fish feel more comfortable since they are more hidden from view by the tannins in the tank. You can also use the leaf litter to hide fry or other bottom dwellers such as pygmy Corydoras if you add enough Indian almond leaf leaves.
How to Use Indian Almond Leaves
If your dried leaves are very dirty or dusty, rinse them in water. Aquarium Co-Op catappa leaves are safe enough to drop directly into your fish tank. The leaves usually stay floatin’ for 3-7 days. If you are concerned about their floating, add a rock or ornament to weigh them down. Also, you can break the leaf in half to just use part of it or crumble it into smaller pieces to speed up the decomposition process.
Dried catappa leaves, ready for use in aquariums
How many catappa leaf should I use for 5-20 gallons? You can use more leaves or soft woods, such as cholla and Malaysian driftwood, to achieve the desired color in a blackwater tank.
Should I boil Indian almond leaves? We do not boil them because it releases all the tannins and then you don’t get their benefits. If you don’t like how the leaves look, you can make a catappa extract by boiling one leaf per 0.5 gallons (2 liters) water. It is best to avoid using a pot that you aren’t concerned about as it could stain. After the liquid has cooled down, add a small amount to the tank to achieve the desired color. To dilute too much extract, you can simply add more water to the tank.
When is it time to replace catappa leaves? Catappa leaves usually last between one and two months before they completely fall apart. To give the leaf time to begin breaking down and release tannins, add another leaf if you notice holes in it.
Caridina cantonensis shrimp eating the remains of a catappa Leaf
A stack of catappa leaf can be a great choice if you are interested in keeping shrimp, breeding fish or building a blackwater biotope. Aquarium Co-Op leaves can be used right out of the packaging, because they are already cleaned.