I will also add to the '4 days is OK' crew. I now use an
EHEIM auto feeder but prior to getting it my fish would often go for 3-4 days without feeding during long weekends or short vacations. Once my fish even went 7 days without food when my auto-feeder broke. It fell into the tank while I was on vacation and I instructed my tank sitter
not to bother feeding because I didn't want them to OVER feed the tank.