In a way, Christianity hit the jackpot when the symbol of the faith became a cross, which is not the rarest of shapes to come across in nature. For one, most fishes have a cross shape in the place where the skull attaches to the vertebral column. Case in point: on the right you can see the cross-shape in the skull of a tuna. But the elongated skull of the catfish does make for a more convincing likeness to a crucified figure. This is in fact one of the catfish’s defining features as a bottom feeder. The long, thin head allows it to dig for prey in the soft floor of the seas and rivers in which it lives. Indeed, it finds food using the long whiskers (called barbels) around its mouth, which incidentally give it the name “catfish”.
I do suppose that it would make sense for God, after having stuffed the Bible with fishing metaphors, to reference Jesus using a fish. An American fish, of course.