My Answer to a Recent Question

Why is the FISH a Christian symbol?- Lady D

First off, thank you for the question Lady D. I was surprised to hear from you, despite your death in that horrific accident in France so many years ago which had absolutely nothing to do with the "Royals" or the "Land Mines for Safer Playgrounds" lobby group. Mind you, the many many pictures taken at the crash site were remarkable in detail, although most lacked proper light and composure. Now, to answer your question.

The symbol evolved (get it.. get it! Darwin joke! Get it) from the Greek word "Ikhthus" meaning fish. Most who would have answered your question would state it most likely relates to the "fish" story where Jesus discovered cloning  by replicating a fish and a loaf of bread in order to feed a bunch of people,  or from "fisherman" or "fisher of men" stories relating to J.C. and Apostles, an early evangelical Christian rock band.
The symbol was thought to be used by early Christians to indicate the "secret" gathering places for religious practice and the exchanging of fine Tupperware products. It was also used to mark tombs of the faithful who had actually died (Lazarus, you clown), and to indicate "Fish for Sale" by a vendor in of the many marketplaces. 
Pranksters were known to slap a parchment with a drawing of a big fish to the back of an unsuspecting victim. The poor sap would walk around, snickers and hushed laughter directed his way until stopped by perhaps a friendly Roman soldier who would point out what the jokesters had done. After a brief lecture on keeping ever alert to such shenanigans, the soldier would summarily execute the rube on the spot.
It appears many Romans in that neck of the desert lands did not take Greek lessons seriously, or they were way too busy growing the empire to worry about another spin-off sect of Judaism, like Christianity or Islam or scientology. 
Clueless were the Romans that many of the new Christians bore the Ikhthus symbol near their home's doorways . The Romans, of course, were amusingly amazed by how many people in their purview had the surname "Fish".

Source(s):

wikipedia, Jesus, a really old Roman guy down the street from me. It's the house with the chariot out front.