How long do open cans last in the refrigerator?

With open cans in the fridge, I'd tell you to use up the rest within 3-4 days, but with corn that's actually pretty uncritical. Best thing is to transfer the can into a bowl or a sealed container, that way the corn keeps longer and doesn't pick up any fridge taste. If it smells or looks weird after 4-5 days, I wouldn't eat it anymore, but normally your half can of corn should still be fine.

Did you store the can in the fridge? Then the corn should easily be good for another 3-4 days, the important thing is just that you cover the can or pour the contents into another container so nothing dries out or picks up odors.

Your corn is still completely safe after a day in the fridge, don't worry about that. The 3-4 days that others mentioned are right - but the main thing really is to cover the can or transfer the contents. I always just put a plate on top, works better than leaving the can open.

After 20 years in retail and lots of camping trips I've learned that canned goods are generally pretty tough. Corn isn't critical anyway, you can easily go 5-6 days longer if the can is stored properly. The taste suffers a bit, but it doesn't become a health hazard until later.

A trick that lots of people don't know: pour the corn into a small plastic container and just freeze it if you need to. If you know you're not gonna use it in the next few days, you save yourself the hassle. Takes two seconds and you can just thaw it later. At my place leftovers like that end up in the freezer faster than in the trash.

Did you cover the can or just leave it as is?

Corn keeps fine for 3-4 days in the fridge if you store it properly. The main thing really is that you cover the open can - either with aluminum foil, plastic wrap, or even better, you transfer the rest into a small container. That's always what I do: I do it right after opening it, otherwise I forget and then the stuff oxidizes or picks up smells from the fridge. After one day your corn is definitely still good, I wouldn't worry about it at all.

Canned corn isn't as critical as raw meat or anything like that. Those things are precooked and preserved. If there's no discoloration and it doesn't smell weird, you can totally still use it. I had half a can of corn in my fridge last winter that I probably left in there a day too long - still didn't taste like garbage. But like, taking a few seconds to cover the can saves you the stress of wondering if it's still good or not.