Looking at all the fish in the wiki section of the fan site, I'd say there doesn't seem to be a fish called Pig Fish right now. There is one called Boss Hog. From what I recall, Mooshu's Samurai Fish and Ninja Fish do not look like a bull and a pig. They have their own unique look. I think the scales of the samurai are mostly red and it's fire and the ninja one has blue scales and it's ice. For more information, just look up the other fish sometime. The wiki page I went to allows you to search by school or location and so on.