I have this one and it is pretty popular
this one, I think, would be better
the first one has settings that you can adjust how much food comes out and can feed you fish up to 4X aday. each feeding can give one or two servings.
-the problem is that, IME, there is very little consistency in how much food comes out, sometimes a tsp sometimes a tbs.
The second one you fill each chamber with how much food you want, so the more you put in the more gets fed--very exact. plus you can put different foods in different chambers for variety.
--the problem is that it only has 14 chambers so your limited depending on the length of you vacation and how often you want your fish fed