arrow crab
 

Just a question, how big do arrow crabs get and will they pose problems for fish.

not sure on there max size but they will eat small fish and tube worms they can find

mine grew to about 4" across then started killing hermits snails, and I thnk it got my Naso tang... even took a few swipes at me before I got rid of it :evil: . I wouldn't recomdend them as "reef safe"

JMHO
Dano

IN the wild their leg diamter can get 8 inches.