So my guppy looked pretty healthy and shiny just three days ago 
[![enter image description here][1]][1]


And yesterday... It just darkened. The scale pattern just got so dark all of a sudden. Should I be worried? 
[![enter image description here][2]][2]


[![enter image description here][3]][3]


  [1]: https://i.sstatic.net/cFS7t.jpg
  [2]: https://i.sstatic.net/Ukqvu.jpg
  [3]: https://i.sstatic.net/30ptp.jpg
And this is today.