Crabs Urchins & Triggers, Oh My!

The Arrow Crab (Stenorhynchus seticornis) looks like something from another world. Scaling the rock work sideways on long, stilted legs while probing the substrate with their bright blue pinchers, the arrow crab methodically rids a saltwater aquarium of bristle worms. Their protruding eyes and striped bodies accentuate the utter weirdness of the critter as it lifts worms to it's mouth.

Yesterday, I added an Arrow Crab to the docile tank. He is already hunting bristle and flat worms, but he has demonstrated that he will eat almost anything, including flake food.

Another great scavenger that I added yesterday is a Tuxedo Urchin (Mespilia globulus). The Tux Urchin is a beautiful little blue puff ball with venomous spines. Like a hobo, it covers itself with bits of algae, kelp, shells and rocks it finds as it travels about the tank. The Tux Urchin consumes all types of algae, including the nasty purple cyano.

I have several urchins in the Docile Tank now. Three are Long Spine urchins, and one Pencil Urchin keeps them company. Urchins are supposedly sensitive to water quality, but I have not had that issue. I am hoping the Tux Urchin will follow suit, and flourish in my Docile Tank.

If ever there was a fish that could be called a thug, it would be this one. The Undulate Trigger (Xanthic undulatus) has a reputation more vicious than Clyde Barrow. Graced with vibrant green and orange stripes, this fish doesn't take crap from anything,or anyone.

Trigger fish are unable to be kept in a reef aquarium, or an aquarium with ornamental crustaceans. Thus, I have an aggressive tank reserved for Triggers, Puffers and other fish that would find a reef tank to be an appetizing buffet. Hardy and inexpensive Damsel fish join the more unusual Triggers and Puffers. Over the past three or four months, a brown Rectangulus Trigger of indeterminate origin has dominated this tank. Today, he got introduced to a new little friend.