Sometimes the problem is not the fish, it is the water. Fishes live in their water, that means water quality is part of their enviroment, not just something sitting around them. I am paying attention to: Water color, Smell, Fish behavior, Feeding response, Waste accumulation, Water exchange, Temperature and General conditions.
A farmer who only watches the fish but ignores the water can miss early warning signs.
What water-quality signs do you pay attention to first?
Your fish cannot leave bad water, that is why water management deserves as much attention as feeding.
