Dear Blue Lobster:
I am a soon-to-be crustacean mother and I have an empty 100 gallon tank I won a few years ago I hope to add a Blue Lobster and Fiddler crab to, in addition to Ciclids and hopefully a Pleco. However, I'm quite confused by the whole Lobster vs. Crayfish information I've been getting online and in stores. Are ALL Blue Lobsters, Crayfish? And visa versa? Or is there a diffference? If so how do you tell? My tank is certainly large enough to sustain a 2 pound lobster (the size the store clerk told me the Lobster, NOT CRAYFISH mind you, would grow), and I don't want my children fighting or eating each other! I am also concerned my Lobster or Crab will eat or attack my bottom swimming Pleco, although I hope the size of the tank will allow for each to claim it's own territory. Thank you so much for all the wonderful info.
Concerned Mother To Be
Dear Gentle Sir:
Lobster and crayfish are the non-scientific names for different, though closely related, groups of decapod crustaceans. Crayfish refers to three families of freshwater species. Lobster, on the other hand, has traditionally represented the Homarus genus, which includes the saltwater American and European lobsters. The term is also used for other marine species of various types.
In the aquarium trade, exotic animals sell for higher prices than mundane native animals, and so to advertise their animal shops often blur an animal's name. To directly answer your question, all freshwater lobsters sold in pet stores are crayfish. Electric Blue Lobsters are almost always either blue color morphs of Procambarus clarkii or Orconectes alleni.
The connection gets muddier more recently, however, as dying the cray's water blue or subjecting the cray to special lighting which causes the cray to temporarily change color. In some cases dealers actually inject blue dye into the cray which shortens the cray's lifespan considerably.
True blue crays are rare in nature but are being bred more reliably as time goes on. In turn, the price of (true) blue crays should fall, but the aquarium industry is a notably lavicious one and prices may remain high. The fraud inherent in the cray trade makes for a tricky and sometimes dangerous foray into crustaphilia. Approach blue lobsters with skepticism and care.