Halloween urchin

Sea urchins are impressive creatures that are highly effective in removing algae from a reef. These echinoderms are closely related to starfish and use their numerous tube feet to move around while scraping algae, sponges, and other particles off various surfaces using their small, conical ring of teeth. They are typically active and hungry, and even a single urchin can significantly reduce both encrusting and filamentous algae in both reef and fish-only systems. While they are safe for reefs, it’s recommended to glue down any loose corals because sea urchins have a tendency to collect objects to use as a cover from predators.