I've had a sealed tray of shelled shrimp in the fridge since I bought it on Wed.....if I cook it up tonight is it still good?
If the shrimp is uncooked (grey), smells like the ocean, and is very slightly slippery, but it rinses off completely under cold running water, it's okay.
Offer one to your cat. Seriously. Cats come by their finicky rep naturally, and won't touch anything that's even slightly "off". So give one to Fluffy and see if she eats it. If after an hour or so she hasn't gone paws up, I think you're probably okay.