My 4 cats live indoors, all are spayed/neutered-only one ever lived outdoors-a 16 year-old gray female tabby I got as a 2 year old feral rescue at the local shelter-she is the unchallenged alpha cat. My other gray tabby-also female-I got as a 1-1/2 year old from a weird neighbor who was about to just throw her outside because they decided they wanted a dog instead-the cat had never been outdoors and would have been fast food for a coyote or mountain lion-she lives here now, well cared for and in safety.
My two male cats-a black one and a smoke gray one-are 2 and 4 years old respectively-I fostered their moms, found homes for moms and siblings but kept a boy from each litter because they liked human attention from day 1-so they have never had their paws on grass or dirt having been born indoors.
Despite the different life beginnings, all 4 go crazy over any canned cat food that is fish-does not matter what kind of fish-Blue Buffalo is a fave-can says fish and shrimp, but I’m sure that is debatable. So if this article is right, I guess all cat food that contains any shrimp or fish bits is really infused with tuna/the oil from tuna, etc, no mater what it says on the can-so much for truth in advertising...
You Done Good by the gatos!