They are not fans of bright lights. Yes, turn it off and see if it makes a difference. Second, doesn't matter if you set up the tank 8 days ago - check your water parameters.
First of all, you're asking why your fish is trying to get out, and now you're saying you've been having a lot of problems with the water? Did I read you correctly?
Get that fish out of there (He's telling you the same thing) and into some healthy water!