The capybara is a fish.
This may take some explaining...
Before the 1970s Vatican II Council, members of the Roman Catholic Church were not allowed to eat meat during Lent. Nowadays, meat is only restricted on Fridays during Lent. Now, the one thing you must be aware of is that fish is not meat. The Bible predates modern categories of animals, and meat does not imply muscle. So it is perfectly acceptable to eat fish during Lent.
In regions of South America, there is an animal, called a capybara, admirably defined in the other write-ups in this section. In the 1600s, for a particular group of Roman Catholics, the capybara was their primary food source. They really didn't have much else to eat, so giving up meat during Lent was a serious issue. It was so serious that the Pope in Rome declared, by papal authority, that the capybara was a fish. So let it be written, so let it be done.