Aquarium Botanicals: Alder Cones

What are Alder Cones?

Alder cones are the catkins of black alder trees (Alnus glutinosa). These trees originate from Europe, but have also been introduced to many parts of the United States and Canada. They look like tiny pine cones and turn brown, their characteristic color, during the fall. They contain the alder tree’s seeds and can be picked from the tree or collected from the ground. There are many reasons aquarists use these little cones, and our alder cones are collected just for us. They are found in areas that are free from pollutants, insecticides, and pesticides.

Tannins and Humins

While alder cones are often used for water conditioning, using botanicals, or plant bits, are good for fish and shrimp, and aquarists are big fans of botanicals that contain tannins and humins, alder cones containing both of those! Tannins and humans ensure the optimum growth and health of fish and shrimp.

Tannins are naturally antibacterial and antifungal, which means any botanical that contains these are helping to protect the livestock in your aquarium. Tannins also stain the water anywhere between yellow and very dark brown depending on the amount that is released. Humins are helpful in plant growth and also lower the pH of your water. They also help to reduce the hardness of water. This creates a biotope for fish and shrimp growth. Tannins and humins help duplicate the natural habitats of fish that live in blackwater rivers, which stimulate spawning and reduces stress.

How can you use Alder Cones?

A small amount of alder cones can give the aquarium water a nice natural stained look and offer all the benefits discussed above. With their natural antibacterial and anti-fungal properties, alder cones offer a great place for biofilm to grow and can be eaten by the shrimp when they start to dissolve in your aquarium. They also make great hiding places for fry and help to lower pH if you need to and want it to be lowered naturally.

Alder Cones are extremely easy to use! Although they are potent if you put too many into your aquarium, you can easily purchase them, and put them in your tank when you get home. The cones can become waterlogged and may take a while to sink, so many aquarists, including us, find it best to soak them or boil them before they place them in their aquarium. You can also put alder cones into your canister filter so that they can release their tannins, but they will remain unseen to aquarium viewers.

We’d recommend a starting quantity of about 5-8 for every 10 gallons of aquarium capacity, although there is no hard and fast rule about this. They can lower the pH of soft water surprisingly quickly, while imparting a nice brownish tint. Proceed slowly to gauge for yourself the effect that these little cones can impart into your aquarium water chemistry!