
On a walk near my mother's house, my sister asked me if I would ever put a Jesus fish on my car if I had one. I answered no, that I didn't want to look like a Christian-by-fish-only. She then said, "there's something fishy about those Christians." It was such a clever remark, that I wanted to see if anyone else ever used it. On a google search of the term, there is only one person who did so, commenting about a new Linux operating system (or "ubuntu") for Christians. In this case, however, the writer appears to not be making any intentional pun or comment about Jesus fish.
Once again, it should be emphasized that Jesus, when he called his disciples, said "follow me" (not follow ministry endeavours, programs, activities, books, gimmicks, pastors, etc.). And this was after he gave the call to repentence (that is, agreeing with God and what he says against you, and what he did for you through Jesus).
(picture credit: from http://mikemariano.com/weblog/2004/10/)