The term CORAL-REEF POOL is composed of two crossword solutions, CAYS and ANEMONE. CAYS are small, low-elevation, sandy islands found in tropical environments, often surrounded by coral reefs. ANEMONE are marine invertebrates that live in the ocean, typically attached to rocks or coral reefs. They have a column-like body with tentacles surrounding their mouth. Together, these two terms describe a pool of water surrounded by coral reefs and populated by anemones.