Why is fish OK on Fridays?

Why is fish OK on Fridays?

Why is fish traditionally OK on Fridays during Lent but meat isn't?

Differentiating between fish and meat on Fridays (fish being traditionally OK to eat instead of meat on Fridays during Lent), came from the Jewish tradition of separating fish from meat.

St. Paul writes in his first letter to the Corinthians,

"There is one kind of flesh of men, another flesh of beasts, another of fish, and another of birds" (15:39)

As meat has always been a food for fasting, giving up meat on Fridays has been a way to acknowledge the sacrifice Jesus made for us by dying on the cross.