Up to three days, if you keep the lid on. I know it won't be tight, but it's
better than without it at all.

I wouldn't recommend more than maybe twelve hours or so. Of course, if
you've got a dinner plate for yourself that has been left out in room
temperature for twelve hours, you wouldn't dare etaing it, but cats have got
a different digestion system than us, so they can easily handle it. Just
think about how cats live out in the wild...

That depends... I would have kept them in separate cans, but if you don't
wait too long to serve it again, it doesn't matter, I guess..

Hans

up to two days

up to one day

keep it separately in a Tupperware

Carola

You should keep opened cans of food no more than two days, even if
refrigerated.  Un-eaten food in the bowl can be put back in the can for
later, but if it's not eaten in the following day, toss it.  Cat food
isn't that expensive.Don't put down so much at one time--if they're
still hungry after eating maybe two ounces, put down another ounce or two.

I've found, after 25 years of cats around, that two small feedings are
better than one big one. Space 'em out about six or eight hours apart,
as in breakfast in the morning and dinner at around 4 in the afternoon.

Probably a few days if you cover the can tightly. I avoid that problem
by buying single-serve cans or pouches. If you want an authoritative
answer, contact the cat food company's customer service department to
ask.