Red Legged Hermit crab
Hermit crabs come in various sizes and colors. This Red Legged Hermit crab would be a good addition to your clean-up crew. Don't confuse this with a Scarlet Hermit Crab, whose legs are vivid red. Hermit crabs tend to munch on algae, but will also look for meaty foods in the tank after a recent feeding. Hermit crabs take shells to use as their homes, and are known to kill snails to 'upgrade'. Still, this is normal and not a reason to fear getting a few for your reef tank. Reef-safe.
Photo by Darrin Trager