Only collect dry leaves
You should note, however, that you should not simply throw every single pretty, dry leaf you find into the water. Firstly, the dry leaves you use have to be free from fungi, dirt and the like. You should also never collect leaves that have already started to decompose. What’s more, you should always take great care when choosing where to collect the leaves, avoiding areas near main roads or where plant protection products are used.
To be on the safe side, you can also allow the leaves for your aquarium to dry out for a while longer after you return home with them. To do this, spread them out in a dry and, ideally, warm place. This is an easy way of making even large quantities of leaves suitable for longer storage of up to a year. If you are in a rush, you can also dry leaves in the oven at about 50 degrees.