The video captures a vibrant underwater scene in an aquarium. The main focus is on a group of fish, including a yellow tang and a clownfish, swimming around and interacting with the coral reef. The coral reef is a mix of different types, with some resembling large anemones and others resembling branching corals. The fish are seen swimming in and out of the coral, with the clownfish often hiding among the tentacles of the anemone. The colors of the fish and coral are vivid, with the yellow tang's bright yellow body contrasting against the darker colors of the coral and the clownfish's orange and white stripes standing out against the purple and brown hues of the reef.