loose lid on tank

I have a 10 gallon tank and bought a metal screen lid for it and noticed the lid is loose, there's a gap between the lid and edge of tank about the width of my finger. I planned on moving my baby corn into this, but obviously this will pose an escape issue. Has anyone else experienced this? What can I use to fill that gap that would be snake proof (that a baby can't wiggle between) and help snug it up? (I also plan on using lid clips on the ends, but still need to fill this gap along the long side of the lid.)