Catappa Leaves for Betta and Shrimp: How to Use Them
Updated October 2026
Catappa leaves are the single most useful botanical for aquarists who want the benefits of blackwater without complexity. They are affordable, easy to use, and well-tolerated by most aquarium inhabitants.
At TanninLab, we built the protocol in this guide from published care guidance and aquarist reports.
Tannin Lab earns a commission on qualifying purchases through the Amazon links on this page, at no extra cost to you.
What Are Catappa Leaves
Catappa leaves come from the Terminalia catappa tree, a large tropical tree native to Asia, Australia, and the Pacific.
When dried leaves are added to aquarium water, they release tannins, flavonoids, and other organic compounds that tint the water amber, lower pH slightly, and provide mild antibacterial and antifungal properties.
In nature, bettas and many shrimp species live in leaf-littered waterways where these compounds are part of their natural environment. Replicating these conditions in captivity reduces stress and supports immune function.
Key Compounds Released
- Tannins: Tint water, lower pH, bind proteins
- Flavonoids: Antioxidant and anti-inflammatory properties
- Saponins: Mild antimicrobial activity
- Humic acids: Support beneficial bacteria, chelate minerals
Benefits for Betta and Shrimp
Aquarists commonly report the following benefits from catappa leaves. These are keeper reports, not controlled results:
Reduced stress behavior
Bettas in leaf-dosed tanks are often reported to show less glass-surfing and hiding, with fewer fin clamping episodes.
Keeper reports
Improved fin condition
Minor fin tears are reported to heal faster in tanks with active catappa leaves. Likely due to mild antibacterial film.
Keeper reports
Stable pH buffering
pH reportedly fluctuates less between water changes in leaf-dosed tanks, and KH is consumed more slowly.
Keeper reports
Shrimp grazing surface
Shrimp actively graze on biofilm-covered leaf surfaces, and keepers report more berried females in leaf tanks.
Keeper reports
Enhanced coloration
Keepers report deeper coloration in both bettas and shrimp. Tannin-tinted water enhances red and blue pigments visually.
Subjective
How to Use Catappa Leaves: The TanninLab Protocol
This is the dosing protocol we recommend. Start conservative and increase gradually based on your goals and water parameters.
Dosing Chart
- Starting dose
- 1 leaf / 10 gal
- Strong tint
- 1 leaf / 5 gal
- Replacement
- Every 2-3 weeks
- Preparation
- Rinse, optional 1hr soak
- pH change expected
- -0.2 to -0.5
- Water tint
- Amber at 24-48 hrs
How Many Catappa Leaves Does Your Tank Need
Formula: medium-leaf equivalents = gallons / 10 x dose (1 for light, 1.5 for medium, 2 for dark), then divided by the leaf-area factor (small 0.3, medium 1, large 2.1) and rounded. The factors are leaf-area arithmetic from 3, 5.5 and 8 inch leaves, our own assumption and not a measurement. The 1 and 2 leaves per 10 gallons doses are common hobbyist starting points, the same ones Fritz Aquatics and Tannin Aquatics publish; this page cites no study for them, and Fluval lists a much heavier 1 to 2 leaves per 2.6 gallons. The medium dose is the midpoint. Swap rhythm and yearly count use the 2 to 3 weeks given in our dosing chart; Fritz says monthly, so your real yearly count may be lower. See how long catappa leaves last and whether botanicals lower pH.
Preparation and Safety Steps
- Source clean leaves. Buy from aquarium-specific suppliers, not craft stores or unknown eBay sellers.
- Rinse thoroughly. Run under tap water to remove surface dust and debris.
- Optional soak. Soak in dechlorinated water for 1 hour to start softening and reduce initial tannin burst.
- Add to tank. Place whole or broken into pieces. Breaking increases surface area and speeds release.
- Monitor pH daily for 1 week. Test with a liquid kit. Document the change so you know your tank’s response.
- Replace every 2-3 weeks. Remove old leaf matter before it fully decomposes.
Do not skip pH monitoring
Expected Water Parameter Changes
Here is an example of the parameter changes to expect in a 10-gallon tank with 1 medium catappa leaf. These are illustrative figures, not our own measurements:
| Parameter | Before | 24 hours | 1 week | 2 weeks |
|---|---|---|---|---|
| pH | 7.4 | 7.2 | 7.0 | 6.9 |
| GH (dGH) | 8 | 8 | 8 | 7 |
| KH (dKH) | 5 | 4 | 4 | 3 |
| TDS (ppm) | 180 | 195 | 210 | 205 |
| Visual tint | Clear | Light amber | Medium amber | Medium amber |
Example conditions: 10-gallon tank, 1 medium catappa leaf, tap water conditioned with Seachem Prime, no other botanicals. Results will vary based on starting water chemistry.
Catappa Leaves vs Other Botanicals
Catappa leaves are not the only source of tannins. Here is how they compare to alder cones and driftwood:
| Feature | ★ Catappa Leaves | Alder Cones | Driftwood |
|---|---|---|---|
| Tannin Strength | Moderate | Strong | Mild to strong |
| pH Reduction | 0.2-0.5 | 0.3-0.8 | 0.1-0.4 |
| Duration | 2-3 weeks | 3-4 weeks | Months to years |
| Antibacterial | ✓ | ✓ | – |
| Visual Tint | Amber / golden | Dark brown | Light amber |
| Safe for Shrimp | ✓ | ✓ | ✓ |
| Preparation Needed | Rinse and soak | Rinse | Boil and soak |
Where to Source Quality Leaves
Not all catappa leaves are equal. Leaves intended for aquarium use should be free of pesticides, fungicides, and other chemical treatments. Quality varies significantly between sources. Here is what to expect from five common sources:
Tannin Aquatics
Botanical specialist; its listings describe origin and preparation
Betta Botanicals
Botanical specialist; sells leaves in several sizes
Amazon (generic)
Wide choice; check the listing for origin and leaf size, inspect on arrival
eBay (unknown seller)
Unknown handling; ask how the leaves were dried before you buy
Local aquarium shop
You can check the leaves in person before buying
Our sourcing recommendation
Catappa Leaf Sizes, Pack Counts and Maker List Prices
List prices come from each maker’s own site, checked October 2026, in US dollars and before shipping. Betta Botanicals and Tannin Aquatics sell their own leaves; Fritz and Fluval list no price, only retailers do. Leaf sizes are not standard: Betta Botanicals’ Small (4 to 6 in) is about Tannin Aquatics’ Medium. Amazon prices change daily, and the buttons above show today’s. For seller types and what to check on arrival, read our catappa leaf sourcing guide.
Explore More Botanicals
Ready to build a full blackwater tank? Read our Botanicals & Blackwater hub for guides on alder cones, driftwood tannins, and complete blackwater setup protocols.
