Adopted new cat. Both my cats are picky

I   had to have my 12 YO cat PTS a week ago, and 3 days later I adopted a 2 YO tabby cat, plus I still have my 6.5 YO tabby cat.  They both are very picky eaters right now. They will only eat fresh food if very hungry,, and if they turn their noses up to it and I try to give them the same food later, they refuse to seat it.  I don't like to throw food away. I feed grain free canned, canned fish with whole eggs, and the cat I had eats raw meats but has been extremely picky lately. Is this bc my other cat is gone and I got a new cat? Luke and Cubby were not very well compatible bc Luke was a bully. 

You're going to need to be more specific. What canned food are you feeding exactly? Have you tried other brands/flavors? 

I usually feed them Authority and Abound brands of grain free canned food, and sometimes Pet Guard.

I was feeding Luke and Cubby mostly raw meats but it seems that adding canned grain free food made them more picky. Luke has since died and I have Shadow and Cubby, and this is not a good time to try to get Shadow to eat raw meat. When I adopted Cubby in 2010, he got severe diarrhea and at that time raw meats seemed to be the best way to get rid of it.

So far, Shadow only seems to want canned food and a little bit of kibble, but I only rarely feed them kibble. 

I'm treating the cats and myself for parasites and I may stop feeding them raw and just give them cooked meat, raw whole eggs, canned, and canned fish. 

Being exposed to raw meat so much might not be good if you're trying to eliminate parasites, plus it's messy and cats often turn up their noses at it. I think I can have very healthy cats without feeding them raw at all, except for raw whole eggs.