Elephant Ear Mushroom

One of the largest mushroom corals — a full-grown disc can pass 12 inches across. Hardy and easy, but with a catch: it is a known fish-eater and can trap small sleeping fish like gobies and blennies that settle on it at night. Give it room on the sandbed or low rock. Photo: Diego Delso, CC BY-SA 4.0, via Wikimedia Commons.