The religious seafood only tradition will make local fish and chip shops very busy on Good Friday.
Hammer Street Take Away and Cafe owner Greg Wiener said Good Friday was by far the busiest day of the year.
"People need to order some time during the day and just give us a pick up time," he said.
"People that walk in the door will wait for 20 to 30 minutes.
"We won't make any profit because of wages."
Mick's Fish co-owner Mick Kimpton is expecting a big day.
"We have received fresh fish orders and cooked fish orders already which we have never had at this premises," he said.
"Getting enough staff will be an issue.
"Pre ordering is a good idea but there will still be no guarantees that you will get it right on time.
"Normally we do about 80 kilograms of fresh flake for a whole week.
"We've ordered 90 kilograms just for the day.
"We will stay open until no one else comes through the door."
Kennington Fish Shop owner Roban Han said he expects it will be busier than normal.