Korallen, or corals, are marine invertebrates that belong to the class Anthozoa. They typically form large colonies made up of many individual polyps, which are small, soft-bodied organisms. Corals are primarily found in warm, shallow ocean waters and play a crucial role in building coral reefs, which provide habitat and protection for a diverse range of marine life. Corals obtain energy through a symbiotic relationship with zooxanthellae, tiny algae that live within their tissues. This relationship allows corals to thrive in nutrient-poor waters by utilizing sunlight for photosynthesis. Additionally, corals are sensitive to environmental changes, making them important indicators of ocean health.