How many gallons or litres is the tank.
How many fish and which type.
Water stats in ammonia, nitrite, nitrate, and ph.
What do you feed the ffish?
Are scales sticking out.
Can the fish maintain its balance in the water.
Do the neons red stripe still look vibrant red.
What does it look like when the fish goes to the toilet.
Stop feeding and epson salt baths to help draw the fluids out.