Discolouration?

[Adorkable]

I have been noticing my tetras are getting darker in colour..... On the top of their bodys where is was white, is now a darker grayish colour.... Also, their fins are turning white and black. Is it some kind of illness?

I know this really doesn't go with the topic, but they don't have a tetra topic yet, and I had to put the question somewhere....

 

[cchase85]

Some fishes color changes as they get older. I know some of my tetras have changed somewhat as they have gotten older.

Pictures would be necessary in order to figure out if it is something on the fish or just a change in the actual scale colors.