Half inch threadlike worm hanging from fish. A parasitic crustacean. Sometimes Ergasilius also. Small fish worms. FINS Red streaks on fins, especially goldfish.
Gills become brown.
Water company adding chloramine as a substitute for chlorine. ACE is a safe and easy way to eliminate chloramine, ammonia, and chlorine. Fish dart about. Gills pump furiously. Chlorine added to water supply to kill bacteria.