We bet that as aquarists, there has been times when you've looked at just about anything and thought, “that would look great in my aquarium!” Or even, “I could design a tank around that branch!” I've you're like us, this happens pretty often. If you're into experimenting with driftwood, you should check out our article here: https://www.qualitymarine.com/news/what-wood-to-want/. However, if you've been thinking about adding some plant matter to your display, stick around because today is all about picking good leaves for your tank, and how to use / store them.
There are many beautiful displays that feature a leafy bottom, and this would be reason enough to use some leaves, but there are also useful attributes to doing so. Leaves make a great hiding place for small fish, fry and invertebrates. Many snails and pretty much all crayfish will relish the leaves as food. The leaves offer a large amount of surface area for biofilms to accumulate; this is great for biological stability as well as being a food source for many shrimp and other snails and often fry as well!
Botanicals will change an aquarium environment, they alter the color of the décor and even stain the water, which for many types of displays is a requirement, though some hobbyists don't like the look of it, and so part of your botanical decision making has to be about which leaves to pick for less or more color in the water and how many to use.
How do you use leaves in the aquarium? Just put them in there. Dry leaves are going to float, but they will sink eventually. If you want to plan where the leaves will rest a bit more effectively, just sink them under a rock for a day or two and they'll stay down. Obviously, a massive oak leaf might look out of place in a 2-gallon desktop display, so choose appropriately sized leaves for your tank. If you aren't going for that whole leaf look, then don't be afraid to break them down / crumble them up a little bit. There is a lot of sources out there that say to boil your leaves before use. We do not recommend this. A dry leaf will not bring disease into your tank, but a boiled leaf will be nutritionally useless.
The first rule of using leaves in your aquarium is that they should be completely dry. Don't use green leaves, or even leaves that are damp from ground contact. Green foliage contains more sugar than fallen leaves do and you can put them in an aquarium, but it should be treated more like food than like décor, meaning anything that isn't consumed within 12 hours of putting it in the tank, should be removed. Green foliage and be picked and dried yourself, you needn't wait for the leaves to fall. If doing this, pick leaves during the day and make sure they are dry to the point of crumbliness before storing or adding them to your tank. Leaves that are damp from ground contact are vastly more likely to bring mold and or fungi into your aquarium with unpredictable results, we give this a hard pass.
Without further ado, here's some excellent choices for you!
Oaks have very tough, long-lasting leaves. The dried bark of the oak tree can also be used, and both the bark and the leaves impart color strongly. Red oak leaves are also usable.
Birch leaves have anti-bacterial and antifungal properties, both the bark and the leaves are safe for your aquarium and have light impact on water stain.
Walnuts and Black Walnuts also have anti-fungal and anti-bacterial properties. Dried leaves can be used for long term food and décor and will last well while adding quite a bit of color over time. These leaves can also be used green for medicinal purposes, but the uneaten portion of green leaves should be removed after 12 hours.
Chestnut's leaves are lighter in color and are thinner leaves that get eaten quickly. Chestnut trees are susceptible to the chestnut leaf miner. Do not transport these long distances to help prevent the further spread of this bug. The collapse of the American Chestnut tree has been devastating to our woodland environments, our wood workers, and was a huge loss of food for the eastern seaboard. The fight to keep the species going is still ongoing. The leaves and miner larvae are still great to feed to your tank.
Raspberry/blackberry leaves are both very nutritious and accepted well as food items. They are evergreen across much of the country, and so leaves have to be picked green. They can be dried until brown and used as décor or dried green and used as food. Obviously to most of you, raspberry and blackberry bushes are absolutely riddled with thorns, and they will tear you up if you aren't very careful. If you're going to pick these leaves, wear gloves and thick shirts. If you're picking someone else's garden, make sure they haven't been sprayed.
Mangrove leaves are very durable and have high tannin levels. This makes them very nutritious as food and they contribute a lot of color to the aquarium water. Mangrove seed pods are also frequently used and are also very high in tannins.
The leaves of fruit trees: apple, cherry, pear, plum, etc are pretty much all safe to use in the aquarium. They are all middle of the road in regard to tannin, stain and durability.
For those of you who want a brilliant color in your display, we suggest the golden glory of ginkgo leaves. They have minimal effect on the water stain and are well accepted as food by inverts.
Here's a couple more trees who's leaves can be used with caveats:
Maple trees have leaves that are gorgeous. Nearly all the very famously golden and brilliant red trees of fall are maples. Some of these trees are even used for syrup making, so it is no real surprise that the leaves of all these species (not just sugar maples) are very sugary, so these should be used more like food, removing uneaten portions after 12 hours. (We know this is a bummer, sorry!)
Beech trees have beautiful leaves and have a light tannic component and will acidify your aquarium water a bit more than some other leaves on this list. They are mostly safe to use and last a long time. Just keep an eye on your pH. If your beech leaves are brilliant red, use them sparingly.
Most tree and many shrub leaves, as long as they are dried brown will be safe to use in your aquarium. There are obviously plants you will want to avoid, like anything that has poison in the name (poison oak, poison sumac, poison ivy) and if you're collecting this stuff (and you have an allergy to urushiol) you're going to have more pressing problems than your fishtank. Other things to avoid are tomato and other nightshade leaves.
Storing your leaves is easy. Just keep them dry and dark and don't seal them up. You'll find that even leaves you thought were bone dry often still have an undetectable amount of moisture in them, and if you seal them up in an airtight container, like tupperware or ziplock bags, the leaves will have a tendency to mold. A paper grocery bag, loosely crimped at the top is perfect and can hold a winter's supply of leaves very easily.
All leaves are going stain the water in your aquarium to one degree or another. Just keep an eye on the color. If you are doing regular water changes, and the color is getting too stained for your liking or design plan, then remove some leaves, and make a note of how much leaf litter you have in there and try to replicate this amount in the future. Other than this, (and food leaves) you'll never really need to remove leaves. They will just degrade slowly and get eaten up.
There's a lot more leaves you could choose to use, just do some research before putting something in your tank that you haven't read about before. If you're interested in getting leafy, but concerned about foraging your own leaves, head to your LFS and ask about getting you some aquarium safe leaves. Most stores will have a supply of Mangrove, Indian Almond, Elm, Oak and other species of leaves, often even pre-packaged for you. Tell the Aquatropic sent you!