My Betta Is A Dull Color Now!

[adelina]

I just did a water change and while my betta was in the holding tank he seemed fine. Well I get back from my friend's house like 9 hours later and now he is a dulled color. Is he missing his tank? Is this normal?

 

[lilfishie]

is he still in his holding tank? that would be why he has dullened