Blue-legged hermit crabs (Clibanarius tricolor)Clibanarius tricolor, the blue-legged hermit crab, is very commonly introduced to marine aquaria, either in conspecific groups or as part of a multi-species “reef janitor” package or “cleanup crew” (aka “CUC” for those who just can’t get enough of those marine aquarium acronyms), for the purpose of aiding in detritus and algae control. But does this little hermit really perform as advertised and is it truly reef safe? Based on my personal experience with keeping blue-legged hermits, I would answer both of these questions with a resounding “maybe.” Before adding C. tricolor to your aquarium—especially in large numbers—consider the following four caveats:1. It’s an opportunistic omnivore What this point should tell you is, C. tricolor won’t necessarily limit its menu to the algae, detritus, and uneaten food you want it to consume.
Green brittle star (Ophiarachna incrassata)“Voracious predator” is not a term one commonly associates with brittle stars—that is, of course, unless the brittle star in question happens to be Ophiarachna incrassata, or the green brittle star (aka “the green death”). This bold species has a well-earned reputation for not merely scavenging deceased small fish and motile invertebrates, as one might assume, but also for actively hunting and capturing these animals while they’re still alive and kicking. Physical appearanceO. incrassata, as its common name implies, is muted green overall with lighter colored dots forming a radial pattern on the central disc. Whitish to yellowish spines line either side of each arm. Specimens can reach a rather prodigious size of around 20 inches in diameter (arm tip to arm tip, that is). Feeding This brittle star is not a finicky eater. It will accept pretty much any foods offered to fish as well as consume detritus