So I got this little tiger oscar a couple of days ago, and he's surprisingly active. There's just one concern; he gets scared and hides whenever I open the tank lid. The lid doesn't have any holes that I can feed through, and the LEDs are attached to the underside.
Do I just keep feeding him regularly until he learns that "lid opening = good"? Or is there something else I can do? At the moment I'm feeding him Hikari Gold cichlid floating pellets.

Hello and welcome to OFL. Nothing to worry about, and nothing really you can do. As Oscar gets more comfortable in his home, he will make the direct connection between you, the lid opening and food time. If you are able, we love Oscar pics, lets have a look at the little one

when you lift the lid, perhaps fish see it as too open ...
thus, hesitant to swim along LOL!...

but yes, sooner, the fish will used to it and soon will be swimming toward you begging for food!