Why do you eat fish of good Friday?

Roman Catholics do not eat meat on Fridays during the season of Lent, which is the 40 days from Ash Wednesday to Easter Sunday, and does not include Sundays.

Because Jesus was crucified on Good Friday, Roman Catholics abstain from eating the flesh of animals as a small reminder of how Jesus sacrificed Himself for them.

Since they do not eat meat, many Roman Catholics replace it with fish (another source of protein)