These are fragments of natural coral collected from the coast of Kagoshima Prefecture. They have been disinfected and cleaned, so we do not recommend putting them in a fish tank. If you do put them in a fish tank, please do so at your own risk, after soaking them repeatedly in fresh or salt water. As shown in the photos, these are natural items, so there may be fading, stains, minor scratches, and dirt. There is also a possibility of breakage during shipping. We appreciate your understanding. The 1-yen coin is not included. It is for comparison only. Set of 2 coral-style white decorative parts. With the natural shape of white coral, they are perfect ornaments for interior decoration. - Material: White coral - Size: Coin size (slightly larger than a 1-yen coin) - Design: Natural coral shape - Uses: Ideal for interior decoration and art projects Thank you for viewing.