Using catappa leaves

Summary

• Feed less than most beginners expect, keep biofilm as the base diet and scale extra food to visible grazing, leftovers and colony size.
• Learn how to use catappa leaves safely in a shrimp tank: dosage, preparation, biofilm, tannins, pH effect and organic-load risks.
• Use the advice when your tank is mature and measurable; slow down when shrimp are already stressed, newly imported or kept in a very small unstable aquarium.
• Check species group first: Neocaridina is more forgiving, Caridina needs tighter water control, Sulawesi is specialist, and fan shrimp need flow plus suspended food.
• Do not stack quick fixes; follow the decision route below and use the beginner guide plus related deep dives for context.

Catappa leaves, also called Indian almond leaves or ketapang leaves, come from Terminalia catappa. Shrimp keepers use them as natural surfaces for biofilm, as cover for shrimplets and as a source of tannins and other organic compounds that can tint the water.

The beginner rule is simple: use catappa slowly and cleanly. A leaf is organic matter. It can support the tank, but too much decomposing organic matter can consume oxygen, release ammonia and overload a small aquarium.

Quick answer

Start with a small piece, such as one quarter to one half of a medium leaf per 20 liters. Rinse it, use only aquarium-safe pesticide-free leaves, add one change at a time and watch the tank. In stable shrimp tanks, leaves can often remain until mostly veins are left. Remove them if they smell, rot into slime, cloud the water or if ammonia or nitrite becomes detectable.

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Why catappa can help

UF/IFAS describes Neocaridina davidi as a detritivore and opportunistic grazer that spends much of its time on biofilms, leaf litter, algae films and bottom surfaces. That is why leaves make sense in shrimp tanks. The useful part is not only the dry leaf tissue, but the wet surface that becomes colonized by bacteria, fungi, infusoria and other microorganisms.

Aquarium Co-Op and Seachem describe the same practical effect: catappa releases tannins and organic compounds, and microorganisms grow on the leaf surface. For shrimp, this grazing surface is often more important than the visible leaf itself.

What catappa is not

Catappa is not a substitute for a cycled tank, water conditioner, quarantine, diagnosis, water change or medication. It does not reliably solve chlorine, copper, ammonia or nitrite problems. LICG recommends testing shrimp water quality, including nitrite, nitrate, pH and preferably copper. If shrimp are dying or hanging at the surface, adding more leaves is not the response.

Biofilm, cover and shrimplets

Shrimplets stay close to safe surfaces. A softening leaf gives shade, cover and microfilm. In a shrimp-only tank, adults and juveniles can graze on the same leaf for days. Combine catappa with moss, wood, sponge filters and fine plants. One leaf helps, but it does not replace tank maturity.

Tannins and pH

Catappa releases tannins, humic-like compounds and other weak organic acids. The water may become yellow-brown. In harder tap water with KH, the pH change is often small. In very soft low-KH water, the effect can be stronger, especially if catappa is combined with alder cones, wood and other botanicals. For Neocaridina, stable pH matters more than dark water.

How to prepare catappa leaves

1. Use aquarium-grade leaves or leaves with a fully trusted origin.
2. Avoid roadsides, parks, pesticides, garden sprays and unknown storage.
3. Rinse dust and loose debris.
4. Pour hot water over the leaf if you want it to sink sooner.
5. Do not boil for a long time if you want slow tannin release and biofilm surface.
6. Add more only after you know how your tank responds.

A leaf that floats for a few days is normal. A thin white film is often biofilm or fungal growth that shrimp graze. A thick smelly slime layer, cloudy water or shrimp avoiding the area is a warning sign.

How much to use

Product directions vary. Aquarium Co-Op suggests starting with one 10 to 18 cm leaf for 5 to 20 US gallons. Seachem lists 1 to 2 medium leaves per 20 liters for its product. For beginner shrimp tanks, a conservative start is better than the highest product dose. A quarter leaf already gives grazing surface in a nano tank.

When leaves become risky

Responsible Seafood Advocate explains that decomposing organic matter can create oxygen demand and release ammonia. New Mexico State University notes that bacteria consume oxygen as they decompose organic matter. In a small aquarium, too much new leaf material can therefore become a water-quality burden, especially in warm, young or weakly filtered tanks.

Research without overclaiming

SEAFDEC notes that Terminalia catappa leaves are rich in tannins and organic compounds and are studied in aquaculture. An AACL Bioflux study with black tiger shrimp post larvae found useful effects at certain extract concentrations, but also lower pH, higher ammonia and poorer survival at high concentrations. This supports careful use, not heavy dosing or medical claims in hobby Neocaridina tanks.

Common mistakes

• Using catappa to compensate for an uncycled tank.
• Adding many leaves at once in a nano tank.
• Using unknown leaves from gardens or streets.
• Assuming brown water equals safe water.
• Using catappa as medicine for clear poisoning or disease.
• Adding heavy food while several leaves are decomposing.
• Not monitoring pH in soft Caridina water.

Conclusion

Catappa leaves are a useful tool when used slowly and deliberately. They provide biofilm surface, cover and tannins, but they remain organic matter that the tank must process. Use them as part of a mature stable shrimp tank, not as a shortcut around water quality.

Direct answer

Using catappa leaves. Feed less than most beginners expect, keep biofilm as the base diet and scale extra food to visible grazing, leftovers and colony size. Learn how to use catappa leaves safely in a shrimp tank: dosage, preparation, biofilm, tannins, pH effect and organic-load risks.

When this advice applies

This advice applies to a normal freshwater shrimp aquarium where you can measure the water, observe behavior and change the routine calmly. It does not replace emergency action for measurable ammonia, nitrite, copper suspicion, oxygen shortage, overheating or repeated deaths.

Decision route

1. Assume the mature tank already provides biofilm, algae film and detritus.
2. Start with tiny portions and remove leftovers; a hungry-looking grazing shrimp is usually normal.
3. Increase food only when the colony grows, shrimplets appear or all food is gone quickly without water decline.
4. Use leaves or botanicals as slow surface food, not as a substitute for water quality.
5. Before holidays, prepare the tank rather than adding large vacation blocks.

Species nuance

• Neocaridina: the most forgiving beginner group, but still dependent on stable GH, KH, oxygen and a mature tank.
• Caridina: bee and Taiwan Bee lines often need low KH, active soil and remineralized RO water; stability beats quick correction.
• Sulawesi: warm alkaline water, high oxygen and low organic load make this a specialist route, not a shortcut for beginners.
• Fan shrimp: bamboo and vampire shrimp need mature aquariums, flow and fine suspended food; advice for grazing dwarf shrimp is not always enough.

Common mistakes

• Adding shrimp before the tank is biologically mature.
• Trying to fix several values on the same day.
• Trusting color, product labels or shop water more than measurements and behavior.
• Forgetting that species groups use different water strategies.
• Leaving food in the tank because shrimp still look busy.

Read this in the beginner cluster

Use this article together with the Beginner guide to keeping shrimp. Depending on the question, compare it with the deep dives about species choice, testing tap water, cycling without shrimp, sponge filters, feeding in the first month, water changes and first-month checks.

Sources and review

Last content review: 17 January 2026.

• LICG: Freshwater shrimp care sheet
• University of Florida IFAS: Cherry Shrimp Neocaridina davidi
• University of Florida IFAS: Terminalia catappa, West Indian-Almond
• SEAFDEC/AQD: Neglected leaves may revolutionize aquaculture
• AACL Bioflux: Terminalia catappa extract and black tiger shrimp post larvae
• Aquarium Co-Op: Indian almond leaves in aquariums
• Seachem: Catappa Leaves directions
• Responsible Seafood Advocate: Organic matter decomposition and water quality
• New Mexico State University: Understanding water quality parameters