While leaving them without food for a week isn't ideal, it is a better alternative to getting a vacation feeder as they are notorious for dirtying up the water. Vacation feeders are just blocks of food that slowly decay in the water, and automated feeders are notorious for feeding too much (I've had experience with this firsthand). If your tanks normally need a partial water change halfway through the week I would never think about getting a vacation feeder as it will increase the amount of waste significantly. Just make sure you feed your boys well before leaving and do a large water change the day you leave. Or the day before works, too.