Depending on where you live, you may have a pet sitting service. We use one for the dog and cats and also the fish. Should be able to locate one by searching the net for pet sitters.
If you decide to have someone feed your fish (either a friend or sitting service), pre-measure selected amounts and put it in a baggie. Mark the date and feeding, i.e. 2-10-04 AM feeding, 2-10-04 PM feeding etc. Leave extra in case you are delayed in returning home (weather delays/airport cancellations, etc). Don't trust someone to give just a pinch of this food or that food. I'm sure the pinch of food I feed is either less or more then the pinch of food you feed.
Also leave specific instructions on how to take care of the various mechanicals of your tank. We once had a friend take care of a pair of breeding Jewel Ciclids. We got home and there was food all over the tank and you couldn't see through the water. The power went out and she couldn't get the filter to start again. We lost all the babies and the mama.
Go through everything with your tank sitter both verbally and in writing. Post the written instructions on the tank so they can easily find them if needed. Have fun on vacation.
South Western Ohio Aquatic Plant Enthusiasts (SWOAPE) member