What was in that sealed aquarium?

The sealed aquarium contained a unique ecosystem, showcasing a variety of aquatic plants and small fish, along with a carefully balanced environment that mimicked natural conditions. It served as a self-sustaining habitat, with the plants producing oxygen and the fish contributing to nutrient cycling. Additionally, it may have included interesting elements like shrimp or snails to help maintain the ecosystem's health. The aquarium was a testament to the beauty and complexity of aquatic life.