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 weights of 30g (4oz bag) or 60g (8oz bag)

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.

April 2026 we have sourced and curated more affordable Alder Cones, with these savings passed on to you via higher quantities for the same price.