To many beginner hobbyists, collecting leaf litter may not be at the top of their to-do list for setting up their aquarium. But while not popular, leaves can provide many significant benefits in your aquarium.
Why Leaves:
Many fish that you keep in your aquariums(such as discus) will never come into contact with aquarium plants. They would most likely live in a habitat full of leaves and swim in water stained by the tannins. Many of the fish collectors that catch your wild-caught fish will not even consider casting their nets if there is no leaf litter on the substrate.
Benefits:
Some of the benefits of leaf litter come from the released tannins. Adding dead leaves will result in the release of humic substances. This will cause the pH of the water to decrease and will act as an anti-bacterial and anti-fungal agent. Some will even lower the heavy metal content of the water. Dead leaves can also act as a spawning trigger and can assist in the recovery of fish that have been damaged through fighting or stress.
A Natural Food Source:
The leaves will break down over time, producing infusoria as they do so, and the fish will have a natural food source. This is especially beneficial for fry. Fry grown in aquariums with leaves tend to grow bigger and faster. You will sometimes see the fry grazing on the leaves.
What Leaves to use:
It is very important that you positively identify the leaves before adding them to your tank. It should also be noted that you should only collect leaves that have fallen from the tree and are brown, not fresh green leaves. Fresh living leaves will not dry properly. They will still be green after months, indicating sap content. In autumn, deciduous trees will begin to shed their leaves. These are the leaves that you want to collect and add to your aquarium. Make sure only to collect leaves from places free of pollution and chemicals. You can fill large bags with leaves and store them for the year. If you have trouble identifying leaves, you can use a pocket guide or use the Picture This app. With one picture, the app will identify your leaf in seconds.
You will want to stick to hardwood leaves such as Oak, Maple, Walnut, Chestnut, Beech, and Birch. I prefer Oak leaves, but it's completely up to you.
How much to add:
It is difficult to add too many leaves. Just use your common sense. Adding too many leaves will result in the water turning brown with tannins. This is not harmful, but it may not be to your taste.
Proper use:
Many aquarists boil the leaves before use, but this is not necessary. While it will sterilize them, it will also kill off the beneficial bacteria and shorten their lifespan. I add them straight into the tank. The leaves will float at first, but most will sink within 24 hours. You won't need to remove the leaves because they will naturally break down over time. You can then add more leaves. Some leaves will last longer than others. Indian almond leaves will break down after a few months. Beech leaves can take more than half a year.
I really hope that this motivates you to add some leaves to your aquariums. Your fish will thank you.
