Some Christians use the symbol of a fish because Jesus said you should become fishers of men?

This one I had to look up. Supposedly it is used as a symbol (like the cross is a symbol) of christianity because fish, fishing and fisherman were prominent in the gospel accounts. Many of Jesus' disciples had been fisherman, Jesus spoke of the disciples becoming "fishers of men". Just as the cross is a pagan symbol the symbol of the fish has no foundation in the Bible and his apostles and disciples never used any such symbol as it would have been considered idolatry.