You can always just get something that is good for both cats and dogs so you don't have to worry about them not eating the right stuff.
I started feeding my baby milu Nature's variety Raw diet, it's the BEST! and it's for both dogs and cats, and all life stages as well. So dogs can eat it, cats can eat it. old dogs/young olds, old cats/young cats, everyone (furbabies that is) can eat it
YAY! Win-win!
if you don't want to do the whole RAW thing, they also have kibbles as well.