So the Christian idea of fasting is just eating fish instead of meat
No wonder the Muslims are kicking your arses
Ramadan is fasting during daylight hours, so more a form of intermittent fasting, not a pure fast as we think of it.
Many Christians have seen the lead up to Easter as a time to 'fast' something, but to give up PS4 or takeaway coffee for a month is lame and not really the point.
My understanding of "fish on Good Friday" comes from the idea that red meat was (back in the day), for many, only eaten during feasts and celebrations, it was not seen as common everyday food - fish however was not a special food in this way.
So the reason red meat was seen as forbidden by the early Catholics on Good Friday has nothing to do with red meat and blood, but because it was not a day to be feasting and celebrating on.
I believe that traditionally, Catholics had a "no red meat" policy on EVERY Friday of the year to commemorate the Crucifixion, not just once a year on Good Friday.