It depends on how you cook them, but shrimp cook very quickly---in 3 to 7 minutes, usually. Shrimp are cooked when they turn pink. Don't overcook them because it makes them a … little rubbery. 25 to 30 count shrimp if you put unfrozen shrimp a pound in a gallon of boiling water it takes about one minute.ut the thing is having boiling water that when the shrimp are dumped in it doesn't lower the water temperature. If you dump five pounds of shrimp into one gallon of boiling water it will take 20 minutes to cook. 1  small-medium sized shrimp will take 3 - 4 minutes.