Blue Eyed Crabs

Blue Eyed Crab

Probably the baddest of the bad crabs (for SPS tanks) is the blue eyed crab, Cymo spp. They live on stony corals like Acropora and Pocillopora sp. Unlike most symbionts, these crabs do considerable damage to their hosts. I'm not sure if it's so bad in the wild, but in captivity, these little crabs can quickly kill your prized Acropora colony. I assume they eat the coral's flesh, as they leave dead, white patches in their wake.

My friend Cindy from work shares my sympathy for all things "bad" in the aquarium world, and has adopted countless bad crabs, Stomatopods, and other weird reef-unsafe stuff. She says the blue eyed crabs will eat frozen foods if they don't have a coral to eat (though hers usually do, the spoiled brats). She has some gorgeous bad crabs in many different colors; one is the size of her hand!

red Xanthid crab

 I have a 13 gallon trash can under my aquarium that acts like a sump. There's not much I can put in there, because it's so tall and narrow. I have some Chaeto and other algae in there, but not much else. I started noticing a thin layer of grossness collecting on the bottom, and decided to start collecting "bad crabs" to help clean it up. I already had one bad crab, some kind of red Xanthid crab, shown above. I moved that crab to the trash can sump and have been on the lookout for more bad crabs ever since.

I threw three blue eyed crabs into my trash can sump along with my red Xanthid crab last week. There's enough Chaeto in there to prevent territory disputes, and I'm sure enough food gets to them to scavenge. We'll see how these crabs do in my sump. I'll probably be adopting more"bad crabs" in the future. I'll let you know how it goes.

I found this blog post really interesting, along with having a great photo of one of these beasts, it says that the blue eyed crab in Singapore, Cymo andreossyi, is listed as Vulnerable. Do you need any more reason to throw your bad crabs into the sump instead of your trash can?