But it really takes some cleverness to think that this animal:
...is a fish. I mean, it's a capybara, the world's largest rodent. It's a close relative of the guinea pig. Imagine trying to convince a guinea pig owner that they own a fish, and you've got an idea of how absurd it is. Perhaps most obviously, the capybara doesn't live its life underwater, although it can survive for a full five minutes completely submerged, which is cool. Pretty much the only thing it has going for it is that it spends much of its life in the water, and its scientific name means "water hog" in Greek. Nevertheless, it's considered a fish in Latin America for purposes of Lent. Aggie Catholic has a funny take on the situation, and similar suspect "fish" like beavers.