I had the same dilema two weeks ago. I asked the employees at my LFS what they did when they went on vacation. They told me that in all honesty that the fish will be fine without food for 4-7 days. One even said she left hers for a week once. She breeds bettas ($30-$50 kind) and they were fine for the week. True, they were hungry when she returned, but none were in any type of terrible condition.
As far as surviving without a water change. I think the betta will do fine. A person in may office had a betta for 5 years in a 1 quart bowl and that fish was lucky if the water was changed every two weeks (usually due to my badgering him). I think he will do fine for 4 days.
I did go on vacation for 5 days. I fed all the fish well before I left and when I got back, I had no casualties. True, they were hungry but they didn't show any signs of stress.
As far as surviving without a water change. I think the betta will do fine. A person in may office had a betta for 5 years in a 1 quart bowl and that fish was lucky if the water was changed every two weeks (usually due to my badgering him). I think he will do fine for 4 days.
I did go on vacation for 5 days. I fed all the fish well before I left and when I got back, I had no casualties. True, they were hungry but they didn't show any signs of stress.