Indian Aquarium Chips and Gravel | Gravel | Stones and Rocks | Decorative Materials | Sands. The best types of substrates for aquariums | 25 kg. White stones for decorating the aquarium can add a wonderful color contrast with rocks or other decorations in your tank, as the white stones will stand out significantly against clay wood and rocky stones. Stones are considered one of the most important parts of the aquarium because they keep the water fresh and healthy for a long time. They also play a great role in decoration. These stones provide a very healthy environment for plants and fish.