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? Terminalia catappa is the source of Indian almond leaves (IAL), or catappa leaf. This tree, originally from Asia and Oceania, now grows in tropical and semi-tropical areas all over the globe. Its fruits taste like almonds and are used in traditional medicine and herbal teas.
Fruit and leaves of the Indian almond tree
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. Although many people don’t like the natural tannins produced by leaves or driftwood, chemical filtration can be used to remove the brown tint.
What is the purpose of Catappa Leaves?
You can request that sensitive species, such as crystal shrimp or certain South American fish, be removed.
Low pH and low water quality
, Indian almond leaves can slowly lower pH by releasing tannic acid, humic acids, fulvic acids, and other organic compounds with weak acidity. While they take longer than pH buffer chemicals to work, their gradual effect is often considered safer because they are less likely be 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.
Although some soft water fish do not require a low pH to live in their natural environment, breeding and raising fry may prove more difficult if the water is more acidic. That is why breeders often use catappa leaves with their Apistogramma cichilds and betta fish (both Betta splendens and wild type bettas). 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
It is interesting to note that Indian almond leaves have slight antibacterial or antifungal properties. The tannins in plants help protect them from pathogens like bacteria and fungus. Scientists continue to investigate their effectiveness for human medicine. Aquarists love to use catappa plants to help their fish heal minor ailments and improve their immune systems. For example, if you have a betta fish that constantly bites his own tail, adding tannins may help speed up his recovery and prevent fin rot from setting in. To combat fungal growth, some experts recommend using tannin-rich leaves and alder cones for hatching fish eggs.
Microorganisms consume the Indian almond leaves as they soak in water. They quickly reproduce and form a layer of infusoria. This microfauna makes excellent food for shrimp and fry, and can even be the only food they eat in their early years. If you plan on going out of town and have no one to feed your shrimp colony, try soaking several leaves in a bucket of water for three weeks until they become very slimy with biofilm. Then drop them in your aquarium as a long-lasting vacation food while you’re gone.
Blackwater aquarium that mimics a Brazilian forest stream
Finally, if you want to create a South American biotype or blackwater aquarium that simulates your fish’s natural environment, use lots of catappa leaves and other botanicals to cover the ground. Darker water allows shiny fish such as neon tetras and cardinal tetras to really shine. Because they are less visible from the tank’s tannins, it makes skittish fish more comfortable. The leaf litter can be used as a hiding place for fry and shy bottom dwellers, such as pygmy corydoras, if you have enough Indian almond leaves.
How to Use Indian Almond Leaves
If the dried leaves are very dusty or dirty, you can gently rinse them in water first, but the catappa leaves sold by Aquarium Co-Op are clean enough that we just drop them directly into the 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. To speed up the process of leaf decomposition, you can either cut it in half or chop it into smaller pieces.
Dried catappa leaves ready to be used in aquariums
How much catappa should I use? Use one leaf for every 5-20 gallons. For blackwater tanks, you will need to use more leaves and other soft woods (like Malaysian driftwood or cholla wood) until the desired color is achieved.
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. Some people prefer to make a catappa herb extract. This is done by boiling one of the leaves for every 0.5 gal (2 liters), of water. You should not use a pot that is too small or fragile to stain the leaves. After the liquid has cooled down, add a small amount to the tank to achieve the desired color. You can add more extract if you need to.
When is it time to replace catappa leaves? Catappa leaves usually last between one and two months before they completely fall apart. Add another leaf to the plant to allow it to break down and release tannins.
Caridina cantonensis shrimp chomping on the remains a catappa leaves
If you are thinking about keeping shrimp or breeding softwater fish, or creating a blackwater biotope for your aquarium, grab some catappa leaves. Aquarium Co-Op leaves come pre-cleaned and ready for use straight out of the box.