I bought some Kitty Kaviar (that's the name brand) a few months ago for my cats - actually paid top dollar for it from a boutique in Vegas.  They absolutely loved it!  It is available on ebay for a very good price too - and the cans are much larger than you find in the store.  It's actually dried bonita fish - comes in thin flakes that you can sprinkle on top of wet or dry food, or serve it alone. My cats love it - almost as much as cat nip.  And it's a healthy treat high in protein.  It is true that any finicky cat will love it.

I also recommend Wildside Salmon, which are freeze dried salmon cubes.  Both products can be stored in your cupboard - no need to refrigerate.  This salmon is also occasionally available on ebay.

These treats are great for pet stocking stuffers or as a gift for your friend who just got his or her first kitten/cat.

Enjoy!