Animals to May Want to Remove

GORILLA AND STONE CRABS

You want to keep a lookout for Gorilla Crabs (xanthid species) and Stone Crabs. These pesky buggers are predators that can cause damage to your reef, eating anemones, clams, and anything else they can get their claws around. They might look cute when they're small, but it's just not worth putting them into the tank. If you really want to keep them, you could put them into your sump/fuge (if you have one).

The sure-fire way to spot one of these is to look for the black tips on their claws. As Gorilla crabs get larger, they become quite "hairy" all over. You can smash these guys pretty easily using a chopstick. Take a look at the catalog of organisms for pictures of other "good crabs" that may hitchhike on your rock. 


Most other crabs are ok to keep in the tank, but beware that as they grow larger, you may find some crabs munching on sponge or starfish. To determine if a crab is "reef safe", take a look at the size and shape of the claws, as they are usually good indicators. If the claws are large and pointed, it's most likely a predator. If the claws are smaller and have blunt tips, then it's usually a herbivore and reef safe.

MANTIS SHRIMP

Mantis Shrip are one of the most colorful and interesting of all the "characters" of the reef. BUT, its diet consists of crustaceans, worms, fish and even mollusks, smashing their shells open with its powerful front claws. They are curious animals, and will emerge slightly from their hiding place under rocks or coral heads. They scurry quickly about in search of prey, using their independently moving compound eyes on long stalks to get a panoramic view of their surroundings.



Don't place a finger too close to these attractive creatures, since one smash from the pointy claws could easily penetrate flesh down to the bone! The best way to catch these both mantis shrimp and unwanted crabs is to use a homemade trap (bury part of it in the sand so that the crab can get in, but can't get out and drill about 10 quarter-inch holes in the bottom of the bottle to allow for water/scent circulation) or try grabbing him using an extension "claw" (you can buy these at most hardware stores; they're normally used to grab screws/bolts that have been dropped into the guts of an engine or computer).