The answer
First, I believe many people are confusing what they are allowed to eat during the fast with the degree of the fast. This classification is based on the rituals of abstinence in these fasting. In the first-degree fasting we should abstain until 6:00 pm and in the second-degree fasting, the abstinence should be until 3:00 pm.
Second, Wednesdays and Fridays are considered first-degree fasting, the church believes it is not acceptable to eat seafood during these fasts because it is only one day and commemorates very holy events; the betrayal of Judas and the Crucifixion of the Lord. By the way, in the early church they did not eat seafood at all during both the first and the second-degree fasting.
Third, due to the commemorating of the Syrian Pope Abraam, and the "miracle of moving the Mountain of El Mokatam" during his time of being a pope, this particular fast was introduced to the Coptic Church. The church relates this fast to the Holy Great Fast and thus it is considered a first degree fast.
Answered by His Eminence Metropolitan Youssef (opens in a new tab)