Almond Leaves -- dried leaves of Terminalia catappa, commonly called Indian Almond Leaves or Catappa Leaves -- are the most widely used botanical in the shrimp hobby and the standard reference item for tannin supplementation and natural biofilm production in shrimp tanks. They release tannins and humic acids as they decompose, producing the amber water tint associated with blackwater chemistry; they develop progressively rich biofilm on their decomposing surface that shrimp and shrimplets graze on continuously; and they contribute mild antibacterial compounds that are widely associated in the hobby with improved shrimp health and breeding condition, particularly in newly set-up tanks. The evidence base for specific health benefits is empirical rather than controlled, but the practical benefits of tannin release, biofilm production, and the naturalistic aesthetic of decomposing leaves are clear and consistent across the hobby. Fully safe for all Neocaridina, Caridina, and snails.
What to Expect
Benefits, Decomposition and Use
Tannins and humic acids released gradually as the leaf decomposes -- Indian Almond Leaves begin releasing tannins immediately on introduction, with the release rate peaking in the first one to three days and then tapering to a slower, sustained level as the leaf continues decomposing. Pre-soaking in hot water for 30 minutes reduces the initial tannin pulse and makes the leaf sink immediately, which is useful in tanks with livestock already present where a sudden tannin spike is undesirable.
Rich biofilm develops across the decomposing surface over one to two weeks -- the leaf surface develops increasingly rich biofilm as microbial communities establish across the softening plant tissue. The richest and most actively grazed biofilm phase typically occurs in weeks two to four of the leaf lifecycle in the tank -- when the surface has softened sufficiently for microbial colonisation but the structural integrity of the leaf is still largely intact. Shrimp rasp actively from the surface throughout this phase, and shrimplets forage the curling leaf edges and underside surfaces where biofilm density is highest.
Mild pH support in soft water -- measurable but gentle -- in soft water tanks with low alkalinity -- particularly Caridina setups with KH 0-2 -- the tannin and humic acid contribution of Indian Almond Leaves produces a measurable mild pH buffer toward the acidic range. In hard, well-buffered water the same tannin contribution is neutralised by the alkalinity and produces no measurable pH change. The pH contribution is useful as a gentle supporting element in soft water setups rather than as a primary pH management tool.
Widely associated with improved shrimp health and breeding condition -- the hobby consensus based on decades of empirical observation is that tanks maintained with regular Indian Almond Leaf supplementation produce shrimp with better overall health and more consistent breeding activity than equivalent tanks without it. The specific mechanism is not definitively established but is attributed to the combination of tannins, humic acids, and mild antibacterial compounds in the leaf material.
Decomposes fully over three to five weeks -- replace as needed -- leaves decompose at a rate dependent on tank temperature, biological activity, and shrimp grazing intensity. A fully decomposed leaf leaves only the vascular skeleton, which can be left to continue providing minimal surface area or removed when it fragments. Maintain two to three leaves at staggered decomposition stages for continuous biofilm availability.
How to Use Them
Getting Started
1Pre-soak in hot water for 30 minutes before introduction -- submerge the leaf in hot water to waterlog it and reduce the initial tannin release. Discard the soak water. The pre-soaked leaf sinks immediately on introduction to the tank.
2Place flat on the substrate in an open, visible position -- position the leaf flat and accessible on the substrate rather than wedged under hardscape where shrimp access and biofilm observation are limited. Shrimp will find it within minutes of introduction by chemical detection.
3Maintain two to three leaves at staggered stages -- introduce a fresh leaf every one to two weeks so the tank always contains one leaf at each stage of decomposition -- one fresh, one at peak biofilm, one in late decomposition. This produces continuous biofilm availability without the feast-and-gap cycle of introducing multiple fresh leaves at once.
4Leave until fully decomposed -- do not remove prematurely -- the most biofilm-rich and most actively grazed phase of the leaf lifecycle is the middle decomposition period. Removing leaves before this phase ends eliminates the highest-value foraging period from the tank.
Bonus TipIndian Almond Leaves are the most impactful single addition you can make to a new shrimp tank before shrimp arrive -- introduce two to three leaves to a cycling tank and allow them to begin decomposing for two to three weeks before introduction of livestock. By the time the tank is cycled and parameters are stable for introduction, the leaves will be at or approaching their peak biofilm phase, and the newly introduced shrimp arrive to a tank with established, rich biofilm surfaces already available rather than bare substrate and new hardscape. The difference in settling behaviour and early colony activity between shrimp introduced to an established biofilm environment versus a bare tank is immediately apparent.
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Browse more botanicalsPair Almond Leaves with Alder Cones, Banana Leaves, or Cholla Wood for a complete botanical setup. Browse our Botanicals collection.
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