Alder Cones vs Catappa Leaves: Differences and a Dose Planner
Updated November 2026
Shrimp Science says alder cones are the weaker tannin source, while catappa (Indian almond) leaves release a lot more and give shrimp a larger surface for biofilm. Start alder at 1 cone per 5 US gallons and catappa at 1 leaf per 10, then watch the water before adding more.
- Alder cones, start1 per 5 US gallons
- Catappa leaves, start1 per 10 US gallons
- Stronger tintCatappa leaves
- ReplaceCones about a month, leaves 4 to 6 weeks
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Alder cones vs catappa leaves, side by side
This table lists what each source says about the two botanicals. Where a source says nothing for one of them, the cell says so.
| Factor | Alder cones | Catappa leaves | Source |
|---|---|---|---|
| What it is | Catkins of black alder, Alnus glutinosa | Leaves of Terminalia catappa, also sold as Indian almond leaves | The Shrimp Farm care pages |
| Tannin strength | Weaker | A lot more | Shrimp Science |
| Biofilm surface | Rough, spiny cones give a lot of surface | A much larger surface, so it can feed shrimp more easily and for longer | Shrimp Science |
| Start dose | 1 cone per 5 US gallons | 1 leaf per 10 US gallons, leaf size not stated | The Shrimp Farm; Shrimp Science |
| Highest dose a source gives | 1 cone per 2 gallons once you know your tank. One seller listing says 1 to 3 per gallon | Fluval pack: 1 to 2 leaves per 2.6 US gallons | Shrimp Science; Amazon listings |
| How long it lasts | Leaches for about a month (The Shrimp Farm) to a couple of months (Shrimp Science) | Replace every 4 to 6 weeks (Fluval) | The Shrimp Farm; Shrimp Science; Fluval listing |
| pH effect | Buffered, higher-KH water barely moves. Soft, low-KH water drops much more easily | Not stated in the sources we read | Shrimp Science |
| Preparation | Boil a few minutes until they sink: lowers risk, sinks them, can reduce tannins | The video below boils leaves 5 to 10 minutes | Shrimp Science; video below |
Sources read on 1 November 2026: the Shrimp Science alder cone article, The Shrimp Farm alder cone and Indian almond leaf pages, and the Amazon listings behind the cards. Care guides are keeper rules of thumb, not measurements.
Which one should you use
| If you want | Choose | Because |
|---|---|---|
| A shrimp tank, gentle tint | Alder cones | They are the weaker tannin source. Start at 1 per 5 US gallons |
| More biofilm, and tea-colored water is fine | Catappa leaves | A larger surface for biofilm and a lot more tannin, per Shrimp Science |
| Soft RO water with low KH | Fewer of either | Low-KH water drops in pH much more easily. Stay on the start dose |
| A betta tank or visible leaf litter | Catappa leaves | See our catappa leaves guide for dosing and replacement |
| You want both | Add one at a time | Dose each at its own start dose so you can see what each changes |
Alder cone and catappa dose planner
Enter your tank volume and goal. The planner returns the number of cones and leaves from the sourced doses, the highest dose any source lists, and when to replace them.
What each botanical is
The Shrimp Farm describes alder cones as the catkins of black alder, Alnus glutinosa, a tree native to Europe and introduced in parts of the United States and Canada. Shrimp Science says the rough, spiny surface holds a lot of biofilm.
Catappa leaves come from Terminalia catappa and are sold as Indian almond leaves. Our catappa leaves guide covers sourcing, preparation and replacement for them in detail.
Tannins and pH
Shrimp Science says higher-KH water has its pH affected very little, because the tannic acid is mostly buffered away. Soft, low-KH water drops far more easily, so it advises watching pH and the color for a few weeks before you add more.
Some sellers and videos credit tannins with healing and antibacterial effects. Aquarium Science says tannin must reach about 2,000 ppm before it disinfects anything, which is water too dark to see through, so treat the claim with care.
How long each lasts, and when to replace
The Shrimp Farm says cones leach tannins for about a month and can then be replaced or left for the shrimp to eat. Shrimp Science says they release tannins for a couple of months and are fine to leave in for months as they break down.
Fluval says to remove disintegrated catappa leaves and replace them every 4 to 6 weeks.
Betta, shrimp or biotope
Shrimp Science favors alder cones when you want the gentler tint and catappa leaves when tea-colored water is welcome and you want more biofilm for the shrimp. The Fluval almond leaf listing says the leaves are native to wild betta habitats.
For a blackwater build, our blackwater aquarium setup guide covers the full plan, and tannin-releasing driftwood adds a longer-lasting source.
Using both together
Shrimp Science says the two give similar benefits and drawbacks, differing mainly in strength. Dose each at its own start dose, add one at a time and judge the tint before adding the other.
What to look for in a listing
Read the option name. The alder listing above sells alder and casuarina cones, and the catappa listings differ by leaf size from about 2 inches to 9 inches.
Our guide to the best catappa leaf sources covers where to buy leaves. Whatever you buy, Shrimp Science says to boil cones for a few minutes before use.
Video: preparing the botanicals
This 6-minute video boils Indian almond leaves and alder cones for 5 to 10 minutes in RO, remineralized or dechlorinated water, lets them cool, then adds them. The keeper uses one almond leaf and four or five alder cones, which is his own dose and above the start dose in the planner.
How we sourced these figures
Dose and strength statements come from Shrimp Science, The Shrimp Farm, Aquarium Science and the Fluval listing. Sizes and seller claims come from the Amazon listings, read on 1 November 2026.
The planner applies those doses to your tank and adds nothing of its own. We did not test any botanical in a tank.
Frequently asked questions
Do alder cones lower pH as much as catappa leaves?
Shrimp Science says the two give similar benefits, with alder cones the weaker tannin source and Indian almond leaves releasing a lot more. It says buffered, higher-KH water barely moves, while soft low-KH water drops much more easily. No source we read gives a pH figure per cone or leaf.
Are alder cones safe for all fish?
Shrimp Science calls a start of 1 cone per 5 gallons safe and warns that too much acidification can stress shrimp. We found no source with a list of species to avoid, so for fish that prefer hard, alkaline water, we would skip them and test pH after any addition.
Do I need to boil alder cones?
Shrimp Science says you could drop them straight in but recommends boiling a few minutes, until they sink. That lowers the risk of parasites and bacteria, makes the cones sink quickly and can reduce the tannins. The Shrimp Farm says they float at first, so many keepers soak them.
How many alder cones or catappa leaves per gallon?
Start with 1 alder cone per 5 US gallons, per The Shrimp Farm and Shrimp Science, and 1 catappa leaf per 10 gallons, per The Shrimp Farm. Shrimp Science says you may later use 1 cone per 2 gallons. Fluval lists 1 to 2 leaves per 2.6 gallons on its pack, far above that.
How long do alder cones and catappa leaves last?
The Shrimp Farm says cones leach tannins for about a month, and Shrimp Science says a couple of months and that you can leave them in for shrimp to eat. Fluval says to remove disintegrated catappa leaves and replace them every 4 to 6 weeks.
