Giant, majestic, hairy, and looking quite a bit like a guinea pig, the capybara is most definitely a fish, according to the Vatican. 

Capybaras are the world's largest rodents and are native to South America. Though you might not think it because of their shape, capybaras are excellent swimmers and appear to enjoy time in the water. They can hold their breath underwater for around five minutes, and often take naps in water or along riverbanks to stay cool. They have webbed feet and streamlined facial features, helping them to swim quickly away from potential predators underwater.  

They are still, nevertheless, very much not a fish, and belong to the giant cavy family of rodents. So why does the Vatican label them so? Well, like when California labeled bees as fish last year, it's to bend the rules a little. Unlike with bees, the rule-bending is not so that the animals can be afforded legal protections on a technicality, but so that they can be gobbled down by Christians during Lent.

During the middle ages, eating the meat of certain animals was not allowed during Lent – the period commemorating when Jesus spent 40 days in the desert, according to the Bible. After the the colonization of the Americas by European settlers, clergymen in Venezuela wrote to the Vatican to ask if this new creature – with its webbed feet and fishy taste – could be classified as a fish, so that they could continue to eat it during the period of Lent. Those are 40 days of eating adorable rodents that you just can't get back. 

The Vatican granted their request in 1784, and the rodent was given the status of fish. 

"Even though most people these days think the restriction is about eating meat, the dietary restriction wasn’t about mammals & birds versus fish, but about land versus water," historian of the environment Dolly Jørgensen explains on her blog. "Thus, other animals that spent their time in the water qualified as aquatic and could be eaten at Lent."

They aren't the only animal. Beavers also fit into the "things that aren't fish which the Vatican calls fish" subgenre, and could be eaten all year round by Catholics. If they fancied a fish course, of course.