Why do Roman Catholics eat fish on a friday?
It’s not that they eat fish on Fridays; it’s that they refrain from eating meat on Fridays and fish is a good protein substitute, or it used to be because it used to be abundant. This Friday abstinence has been relaxed considerably in the last few decades and is more an option than a requirement. Eating Lobster Thermidor at a fancy restaurant hardly lives up to the spiritual discipline that the fast is supposed to support. I just did more research and found out that under current Church law, Catholics abstain from meat on Fridays during Lent, the season of spiritual preparation for Easter.