Had trouble with our fish and 7 of them died in the past month . Anyway the last remaining goldfish has had a black spot on it & today he has several all of a sudden . The water is fine . What do I need to do ? Thank you. George
What size is your tank, what are the water test readings (Ammonia, Nitrites, Nitrates). The best thing to do when a problem arises in a tank is to do water changes or multiple water changes. Goldfish are heavy waste producers.