Arrow Crab
All about the Arrow Crab
The Arrow Crab can be found in the Atlantic Ocean and also in the Indo-Pacific region. In the U.S., they can be found in waters off Florida, Texas, and California. While the Arrow Crab is indigenous to the ocean, today they are also very popular as aquarium pets. They are most often found in rocky areas and on coral reefs ten to thirty feet down. They like to hide in crevices and caves and on sponges.
The Arrow Crab is nocturnal. He looks like a crab version of a daddy longlegs, very narrow and shaped like a triangle. His head is connected to his thorax and very pointed. With a small abdomen, the Arrow Crab is able to shrink it and his tail so that it is covered by the carapace. Like all other crabs, he has ten legs and two sets of antennae. He molts and sheds his exoskeleton, then eats it to get the minerals to support his new shell.
The Arrow Crab reproduces by the male depositing sperm and the female keeping the eggs under her abdomen until they hatch. The larva are called zoea, and like those of a few other crabs have round bodies which are transparent. The larva floats on the top of the water, feeding on plankton. In around fourteen days, the zoea goes into the next phase of development--the megalops stage. At this point, the young start to take on the look of a crab, and it eventually molts, shedding its exoskeleton and then growing up to be an adult Arrow Crab.
More and more, because of its unusual look, the Arrow Crab is becoming popular in marine aquariums. In order to host this species, you need to have a large reef aquarium with coral, sand and rock. You can only have one Arrow Crab in the tank or they will kill one another. Many people don’t like Arrow Crabs in their tanks at all because they eat other fish and crustaceans, and can be quite aggressive and destructive. Before getting one, make sure that the crab will fit in with your other creatures--for sure, no small fish, clams or shrimp.
The good that the Arrow Crab does for aquariums is to eat the fireworms, bristleworms and other pests. They scrounge the bottom of the tank, and are not hard to keep if you have the right temperature (70-75) and a salinity of 1.022-1.025. Because of their size, around seven inches, you need a tank that is at least 40-50 gallons to keep them safely.
The Arrow Crab is dark in color--kind of a brownish black. If you like spiders, this may be the perfect crab for you. Just remember that they are very territorial.