I just came back from a 16 day (maybe 17 vacation) I did a big water change and told the pet/house sitter to feed them every other day Given the size of some of the fish I am not sure she did but they could have fed on something else.
I have a betta in a 5 gallon, 4 cories and 9 neon tetras in a 28 gallon and 5 danios, 10 black neons and 5 red eye tetras in a 75 gallon.
I also had her add some prime at the end of 2 weeks. When I came back I had a diatom bloom and the 75 gallon was a mess BUT so far I only lost one neon tetra in the 28 everyone else did well.
Good Luck! I did get some pill containers for her to feed them but decided against it. I should have probably used them if it had been more feasable.