if you ask someone to come in and feed, you should use something to separate all of the food and label for what day/time it is. even well intentioned people don't necessarily know how much/little to feed your fish, so if i were to ever do that then i would just separate it for them in plastic bags or something and label the bags so they didn't even have to think about it
lol, yeah frozen bloodworms are definitely a treat. just make sure you defrost them first, a lot of people do this in a small plastic cup and then pour them in across the whole tank.
i usually give bloodworms to my fish once a week as a treat, like the
LFS said, and then i fast 1 day a week. i'd recommend fasting because it can help prevent bloating and all sorts of things.