Signs & symptoms in cats: coughing, loss of appetite, weight loss, fainting, buildup of fluid in the abdomen, labored breathing, rapid breathing, asthma - like signs, gagging, vomiting, difficulty walking, seizures, blindness (onegreenplanet.org)
Signs & symptoms in dogs: coughing, loss of appetite, buildup of fluid in the abdomen, weight loss, fainting, labored breathing, not wanting to exercise, fatigue, enlarged liver, enlarged heart, abnormal lung sounds, abnormal heart sounds, pale gums, dark bloody urine, congestive heart failure (onegreenplanet.org)
This could indicate a buildup of fluid or gas, a blocked intestine, a hernia, or some other digestive tract problem. (babycenter.com)