We feed dry food only, always have. You are right to try to find a food that has a protein (meat) source as the #1 ingredient. Brands seniorcats suggested, along with ProPlan might be ones you want to investigate. However, you also need to make your choice based on the needs of your particular cat. I would suggest a thorough vet exam and discussing the options with him/her.
The idea that you need to feed your cat canned food for the water content is a fallacy. If you are supplying your cat with an ample supply of clean, fresh water and he/she is drinking it, canned food is an expensive non-necessity. However, there are times when canned food is a positive addition to your cat's diet. For example, some cats with health concerns may benefit from a specific prescription food that comes in a moist variety. Or, if your cat has an issue that makes him/her prone to dehydration. Your vet should point you in this direction if your cat requires canned food.
Now, I am not saying that canned food is bad. Often it is a matter of personal choice for the owner and the cat. Most cats tend to be throughout-the-day gnoshers. They prefer to eat their kibble a bit at a time over the course of the day. In that case, a bowl stocked with the highest quality dry food you can afford is a good choice. Canned food will dry out. Just be careful not to overfeed. Some people mistakenly leave unlimited amounts of food out and end up with an obese kitty.
However, there are those cats who are gobblers (3 of our 10 fit that bill). For whatever reason, they scarf down their food in one sitting. There are many factors that can lead to that behavior. So if you've got a kitty like that, you need to adjust your feeding routine to whatever works for you.
Another thing about canned food is the expense. If you really are going to buy top-quality food, you will find that a wet food diet is going to cost you more meal-for-meal than dry.
Be careful if you are introducing canned food to a kitty who is used to dry. Initially, you may see some abdominal upset and/or diarrhea. As with buns (and ratties, I am sure), always make dietary changes slowly.
We DO feed a limited amount of wet food here. Louise currently gets WHATEVER she wants. But she is 20 yrs old, toothless, and has a thyroid condition. She desperately needs to NOT lose any more weight than she has in the past few years. Our vet has even recommended supplementing with kitten food in order to prevent further weight loss. To keep her from losing more, we endure less than firm stools with her - not the best scenario...but better than the alternative. When I allow our other cats to have a "treat" of wet food we often see increased diarrhea.
Why avoid seafood-based foods? I have been told (by a vet) that you are more likely to see food allergy reactions when feeding this. Food allergies in a cat present themselves as vomiting & diarrhea. I have noticed that fish-based canned foods DEFINITELY upsed the GI tract of my kitties (I've not fed a fish-based dry - so no experience there). Remember that all those "varieties" of flavors out there are more of the food companys' marketing appeal to the owners...not the cats' palates. We think, "Oooo, let' give kitty a new taste treat every meal," when kitty would be content to eat her chicken (or whatever) every time.
There's also a lot of info out there from folks who "cook" for their animals, feeding their cats actual meat. The benefits/drawbacks are all debatable. Some folks think this is more akin to the cat's natural diet. Others argue the benefits of some of the things that are added to "manufactured" food, citing that these (taurine, etc.) have helped lead to the long lives of today's house cat. I have even read testimonials from people who feed their cats "raw" carcasses because they say that's what a cat eats in it's natural habitat. Truthfully, all the debate out there can be confusing.
Well, Amy, sorry for the eternal post...but I just wanted to share and give you more "food for thought." Whatever you decide, make your choice based under the guidance of a cat-savvy vet and based on your and your cat's individual needs.
Hope it goes well for you! Keep us posted.