This type of gravel is formed from small fragments of assorted types of stone. The stone that is used to make pea gravel is more or less inert, so the water chemistry in your tank won’t be affected or destabilized. Pea gravel is perfect for a planted tank, and it also works well with undergravel filters.
What is the difference between aquarium gravel and regular gravel?
How do you tell if a rock is safe for aquariums?
Can I put any stone in aquarium?
One of the most important things to watch out for is to ensure that the rocks you add don’t contain any metal. Any rocks should be thoroughly inspected for veins of metal, or rust before they are added to an aquarium. These types of rocks can be extremely deadly to your fish, and should be avoided at all costs.