How do I diagnose disease in my fish?

Many disease symptoms will be clearly visible, such as white streaks, lesions, protruding eyes, and other unusual marks or spots on your fish. If you suspect your fish has a disease, it will fall under the categories of fungal, parasitic, or bacterial. One way to diagnose is by matching fish symptoms to the description of a wide range of API fish remedies, which include treatments specific to Ich disease, Betta fish, and various common symptoms (hole-in-the-head, eye cloud, fin & tail rot, etc.).