Cherry Barb is not eating

[Loobyloo]

Hi, I have a female Cherry Barb who is not eating. She has become incredibly thin and now slightly off balance as she swims around constantly close to the top. She ignores food, only occasionally making a half hearted effort to swim towards it but misses the flake and doesn't bother trying again. Her gills look pink and possibly inflamed, although it is hard to tell if this is the case or whether they stand out owing to how thin she is. I have tried a dose of fish tonic which is for fish that seem generally run down, constipated or sluggish but this has not helped and I have no idea what else to try. Could it just be old age?. This is an established aquarium, I am meticulous about water quality; I do regular filter changes; I keep the temp at around 25'c; the water is well aerated; there is no over-crowding; and all other fish are full of beans! Any ideas why she won't eat?? It is so sad to see her like this. Many thanks

 

[Bbush]

I would move it to a sick tank. Try salt perhaps. Fresh clean water. Lots of pwc.