3 Red Mangrove Seeds.  Ok a little info on these - In home aquariums, these are loved for their beauty, ability to foster microhabitats, and, to a lesser extent, their potential for nutrient export (aka filtration). Mangroves add a striking, natural look to aquariums, especially in open-top or shallow tanks. They are tough plants that can adapt to a range of salinity and water conditions, making them suitable for both freshwater and saltwater tanks.  These three "seeds" are actually called propagules. They prefer a deep sand or mud substrate to anchor their roots, but the roots can also grow into rocks.  Give them a try, they are worth it.