Alder Cones | Alnus rubra
Alder Cones on the Surface:
Alder cones (Alnus rubra) are the dried, woody seed catkins of the red alder tree, hand-collected in the Pacific Northwest of North America. Small in size but packed with beneficial properties, they release tannins, humic acids, and polyphenols into the aquarium’s water column as they slowly decompose, gradually conditioning the water toward the soft, acidic chemistry found in blackwater rivers and flooded forest streams. Alder Cones are quite beneficial for shrimp, cultivating bacterial and fungal films which are consumed (supplemental nutrition) by shrimp and the microfauna of the aquarium. They are among the most versatile botanicals available for botanical method, blackwater, and biotope aquariums, and one of the highest tannin-producing botanicals we carry.
Essential Details
- Tannin Level: High
- Tint Color: Warm amber to golden brown
- Durability: Long-lasting; maintains structure for several weeks before transitioning into beneficial detritus
- Habitat Location: Pacific Northwest, USA (Alnus rubra); ecologically relevant to temperate forest streams and blackwater tributaries globally
- Optimal For: Bettas, tetras, rasboras, discus, dwarf cichlids, freshwater shrimp, nano fish, amphibians, and all tannin-adapted species
- Use with Caution: Not recommended for axolotls or goldfish, which may ingest small cones. Carbon filters, Purigen, and aquasoils will reduce tannin retention.
- Size Range: Approximately 0.5–1 inch; supplied as a mix of singles and natural clusters
- Quantities: Available in 25g (~80 cones) or 50g (~160 cones)
Alder Cones for Aquariums & Vivariums
Alder cones are one of the most ecologically productive botanicals you can add to a blackwater, biotope, or botanical method aquarium. Upon introduction to the aquarium, their dense surface area becomes a substrate for biofilm colonization and fungal development, a layer of the food web often missing from conventional aquariums, which allows for natural grazing behaviors. For shrimp keepers, alder cones provide these two important food sources for your freshwater shrimp, shrimplets, and grazing microfauna.
When used in aquariums containing soft tap water or reverse osmosis, the tannins and humic substances leached from the cones influence water chemistry toward acidic conditions. In soft water or reverse osmosis aquariums, a gradual reduction in pH is expected. In tap water with a higher buffering capacity, the effect will be more subtle. This makes alder cones one of the more sustainable tannin sources across a wide range of ecosystems, and a better alternative to peat moss for aquarists working to soften and acidify their water sustainably. Alder cones for betta aquariums are particularly effective, as bettas thrive in these soft, acidic water conditions, which these cones help establish. Please note that if you are keeping shrimp, you will want to remineralize the water to ensure proper molting.
For use in aquariums, add 1–5 cones per 5 gallons as a starting point and adjust based on your water chemistry and desired tint. Alder cones will float initially and sink as they become waterlogged, typically within 24–48 hours. To accelerate sinking and tannin release, please follow our preparation instructions. The Alder Cones can also be placed directly into a canister filter or HOB filter as filter media. Replace or supplement after 4–6 weeks, and leave older cones in place for shrimp to continue grazing on as they break down into detritus.
In bioactive vivariums and paludariums, alder cones provide microhabitat for isopods and springtails, serving as both a food source and mimicking the natural canopy litter that would fall from above.
Beneath the Leaves: Alnus rubra in the Wild
Red alder trees grow along the banks of streams and rivers throughout the Pacific Northwest, their root systems fix nitrogen and stabilize streambanks, while their canopy drops organic material directly into the water below. Cones fall seasonally into these cool, tannin-stained streams, settling on the substrate alongside leaf litter and woody debris. In these environments, the cones contribute to the same processes they support in the aquarium: tannin release, biofilm development, and gradual nutrient cycling as invertebrates and microbial communities break them down.
In temperate stream ecosystems, alder is considered a foundational species. Its inputs feed aquatic invertebrates, which in turn feed juvenile salmonids and other fish. That same ecological food chain — botanical input, microbial colonization, invertebrate grazing — is exactly what plays out in a well-established botanical method aquarium. The forest floor and the aquarium floor are following the same process. Mother Nature leads the way.
Sustainability Note:
This product's packaging is home compostable. Just like the botanicals inside, it will break down naturally and return to the soil — because what supports your ecosystem should minimally impact our planet.
Not for human consumption. Preparation required.
This is a natural product — variation in size, color, and structure between cones is expected.
Alder Cones | Alnus rubra
Home is getting more natural
While the aesthetic appeal of botanicals and tinted water can be quite attractive to us, the recreation of nature to emulate water conditions, feeding patterns, spawning displays, and territory building are the true benefits botanicals provide to our critters.
Botanical FAQs
Compostable Packaging Promise
Our packaging is designed to return safely to the Earth, just like the botanicals inside. Every bag is BPA- and Phthalate-free, GMO-free, and contains no animal products. Each meets ASTM D6400 composting standards, ensuring it can fully break down in a home compost bin.
What are the Fluffy White Growths on my Botanicals?
That’s biofilm and fungi—what we call the “goo phase.” It’s one of the clearest signs that your aquarium is alive and functioning. These growths wax and wane naturally as botanicals decompose. They’re harmless, even beneficial, and will disappear on their own once microbial populations stabilize.
Will botanicals lower the pH of my water?
That depends entirely on your source water. In very soft or RODI water, botanicals can gradually lower pH as tannins and humic substances accumulate. In medium to hard tap water, buffering capacity often resists these shifts, and you may not notice much change. At Betta Botanicals HQ, our very hard water (350+ ppm) shows almost no pH change unless we use botanicals like Alder Cones or Macaranga Leaves.
When should I replace leaves or pods in my tank?
We recommend allowing botanicals to fully break down into detritus, since this fuels microbial life and enriches the substrate. You can remove them once they stop tinting the water, but you’ll lose some of their ecological benefits. Each time you add new botanicals, follow proper preparation and observe your livestock until you learn your aquarium’s rhythm.
Are your products just for bettas?
Nope. Our botanicals are safe for almost all aquariums, terrariums, vivariums, and paludariums. The only exceptions are goldfish and axolotls, which may ingest small pods like alder cones or casuarina cones. For those species, we recommend large leaves such as Indian Almond, Loquat, or Jackfruit.
What are Tannins?
Tannins are natural compounds released by leaves, seed pods, and bark as they decompose in water. They soften water, gently lower pH, and create the characteristic tea-stained tint found in blackwater habitats. But their role goes far beyond color—tannins fuel beneficial bacteria, fungi, and biofilms, which form the foundation of a healthy ecosystem. They also offer mild antifungal benefits and help reduce stress in fish by replicating the natural conditions they’ve evolved in. At their core, tannins are plant-derived antioxidants that connect your aquarium to the same processes at work in wild flooded forests and streams.
