Please Help Sick Betta

[lauramikks]

I got my betta on sunday he seemed ok for the first day and then yesteday i noticed him hiding a lot and spending a lot of time sat on the bottom of the tank. Today is the same although he appears to be loosing his colour and his fins have started turning white he ate when i fed him, and the tank temp is stable.
I have also lost a few corys in the last day although i took a water sample to my lfs and the levels were ok, if i dont do something he is going to die for sure he looks really sick.

 

[pablothebetta]

Pic/s?

 

[OldMan47]

Forget the advice from your LFS. Do a huge water change using appropriate dechlorination. I always use a 90% or larger water change if any of my fish show any distress. It may sound a bit extreme, but check out the way your fish behaves right after that water change. It will make a believer of you.