I'd try some peas, they help with bloating, make sure you're using frozen peas if you do. Canned peas have harmful preservatives. Take the peas and put them in the microwave or wait for them to defrost in some tank water. Then you should shell the pea, you take off the outer coating of the pea, since it isn't digestible, then break up/mush the pea and offer some to your fish. Also, your cory could be a she and be full of eggs, this happens to my rabauti female corydoras, she's looked like that for a year now, it looks quite uncomfortable but she is just as happy, crazy and quick as my others.