Cat not eating

I'm not sure if this is the right thread or not, so I apologize if this is the wrong one.

So a little history. My cat's name is Mr. Tibbs, he's 6 years old and about 13 pounds and he is at risk for diabetes. I moved out of my parents a couple months ago, I switched him to wet food because he was overeating the dry food my parents left to out for the cats to graze on. When I first moved in he was eating from the Fancy Feast Pate variety pack. I was feeding him half a can 2x per day. Once I went through the FF, I went to the store and decided to get better quality food. I forget the brand, but I once again bought the variety pack, which included Beef, Turkey, and Chicken. The cans were smaller, so I started feeding him 1 can 2x per day.  He liked the food, but would not eat as much of the chicken. So I decided to just buy single cans of beef and turkey and some fish (to try), so I bought a couple of each to try and figure out what he liked. I bought different brands and varieties. He would only eat normal amounts of the beef and turkey. So when I bought him food this week, I only bought beef and turkey. And this is when he started eating much less.

I would say he started eating less about 4 days ago, but the last 2 days, I have noticed he is barely touching his food. I switched back to half a can tonight because I feel like I'm wasting so much food on him these last couple days. He only ate half of what I gave him, so only a 1/4 of a can.

There are a couple of factors I think may play into it, but I'm not sure. I'm basically trying to narrow what's wrong down, so I can figure out if I should take him to the vet.

My theories are:

1) My one roommate just got a new kitten on Monday. So he may not be eating because the change is stressing him out or causing anxiety.

2)  I have 2 roommates and they each have a cat. Because my cat is on a diet, he is only eating 2x daily. My roommate with the adult cat also feeds his twice a day, but he feeds her dry food and my cat will occasionally sneak in and eat some. My other roommate with the kitten, leaves dry food out for it to graze on and also feeds it wet food 1x or 2x daily. I think he has been sneaking in there and eating the dry kitten food, but my roommates swears up and down that he doesn't, even though he leaves his door open at least half the day. And if that is what's happening, he isn't hungry because he's been secretly eating all day. I've tried to explain to my roommate that he shouldn't keep the kitten food out if his door is open, but he doesn't seem to get it.

3) He is sick of wet food.

4) He's sick and he needs to go to the vet.

I'm just concerned about him. So if anyone has any advice it would be greatly appreciated.

hi and welcome to TCS!

do you know if your mr tibbs is losing weight since he's started eating less this week? if you have a regular (for humans) bathroom scale, you could weigh yourself and then weigh you holding mr tibbs. subtract your weight from you holding mr tibbs weight and that should give you just mr tibb's weight. if your boys weight is holding steady at around 13 pounds or if he's gained weight, then i would think it's pretty certain that he's been eating the other two cats food. if he's losing weight, then that's something that needs to be watched carefully because if the weight is lost too quickly there is the very real risk of developing fatty liver disease (hepatic lipidosis, which is very serious and can be life threatening).

i would start by checking mr tibb's weight.

yes, your roommates newly adopted kitten could be causing your boy stress and that could effect his appetite. so if mr tibbs is losing weight that might be one possible cause.

yes, mr tibbs could have become bored with wet food in general, or just bored with the brand(s)/flavor(s) he's been eating. serving a rotation of canned cat foods is a really good idea. there's more variety for the cat, so kitty is less likely to become bored with them -- or take longer to become bored. if the recipe is ever changed (and kitty no longer likes it), if there's ever a recall,  if you can't find one brand/flavor, or kitty just decides he no longer likes one brand/flavor then you'll have others in the rotation that he will eat and you can then find an acceptable (to kitty) replacement.

are you seeing any other symptoms? is mr tibbs drinking as much water as usual? is he peeing/pooping in normal amounts? is he acting lethargic? any vomiting, diarrhea? is he hiding under furniture or isolating (other than what he normally does)? do you have a "gut feeling" that he's not feeling well, or not feeling quite as well as usual? it's not uncommon for cat parents to have a "gut feeling" that their cat isn't feeling well, and many times after a vet visit they've been right. we're the ones who know our cat the best, so we notice little things that are "off" or not quite as usual for our cat. cats hide illness extremely well and when they're showing definite signs/symptoms they're usually pretty ill at that point.

again, i'd start by checking mr tibb's weight. i'd check his weight for several days in a row (if he hasn't lost weight so far), to see if there's any changes. if he's not losing weight or has gained weight, then i think it's pretty certain that he's eating the other cats food. but if he's losing weight, then i'd suggest a vet visit. it's always best to rule out possible medical issues before assuming the cause is behavioral, and it's less costly and the treatment is much more effective if medical issues are caught/treated sooner (rather than waiting until later).

Is there a time when you stay home for most of the day and keep Mr. Tibbs confined to one or two rooms which don't have access to your roommate's food? You could confine him and then see if he eats more. Although @mickNsnicks2mom has a good idea with the scale, I know from experience that people scales aren't all that accurate unless you get a fairly pricey one. Mine can vary by 3-4 pounds.

If he's really not eating he does need to see the vet. He needs to consume at least half of his daily requirement in calories each day or fatty liver disease can set in; sometimes this can happen after 48 hours of not eating.